STUDENTS’ DIFFICULTIES IN CHANGING PASSIVE VOICE IN INTERROGATIVE FORM

The paper entitled “Students’ Difficulties in Changing Passive Voice in Interrogative Form” is written to analyze the students’ difficulties and the causes that make them difficult to change passive voice in interrogative form. The research was conducted to the third semester students of English Education Study Program, Faculty of Teacher Training and Educational Sciences, Pakuan University. The writer applied descriptive method and the data were gained from documentation, questionnaire and interview. All instruments are given to 28 students who became the respondents. In order to validate the data, the interview to the lecturers are also done. Based on the data, the writer finds out four types of students’ difficulties; they are difficulty in changing the position of subject and object, difficulty in determining appropiate auxiliary verb used, difficulty in determining which sentence can be changed into passive and difficulty in deciding the past participle. The causes also are found of two factors are internal factors such as first, students’ motivation; second, students’ intelligence and aptitude; at the last, students’ personality and learning style. Besides, external factors such as the material, the facility and atmosphere, as well as the lecturer’s explanation. The most factor that causes students’ difficulties are students’ motivation (internal factor) and lecturer’s explanation (external factor). As suggestions, students must increase their motivation especially internal motivation, basic skills in English grammar especially tenses then more pay attetion to the lecturer’s explanation and always ask the lecturer to minimize the difficulties.


INTRODUCTION
Most of English learners get difficulties to understand their English materials especially focus on written language when they are learning grammar. Learning written language consists of learning how to write in writing, how to apply English well based on the rules, and how to choose the best word in constructing sentence. Learning grammar is one of the ability to comprehend written English by knowing the rules and applying those into written English. Thornbury (2003:1) states "Grammar is a description of the rules that govern how language sentences are formed". It means that when learning grammar authomatically learning structure. English structure has many rules and mostly students get difficulties to apply those rules. However, structure should be learned to avoid the learners for making mistakes.
One of grammatical sequences in English structure is passive voice. Passive voice is rarely used in daily activity. Some writers (Frank, 1972;Gambley and Patzold, 2004;Swan, 2005) state that passive voice commonly used in academic and scientific writing such as in making news, newspaper, technical or business reports and in making research proposal. However, the students who learn language must comprehend passive voice to increase the ability in constructing sentence. Learners who have learned passive voice get some difficulties to change passive sentence especially in interrogative form.
They still get difficulties to construct passive sentence even they have known the pattern of passive voice.
The passive form has some rules that should be known when applied in making sentence such as the formula, the verb which is used, the auxiliary, and the change of function. The passive voice is formed by using to be and past participle. Based on the early observation, some students have problem when they change passive voice in interrogative form and also many students make some mistakes in changing passive voice. Therefore, the writer is interested in analyzing students difficulties in changing passive voice in interrogative form.

METHOD
In conducting the reasearch, descriptive method is used to analyze the students' difficulties and students' causes in changing passive voice in interrogative form.
The data are gained from data collections of students' work followed by questionnaires, and interview. First, the students' work is analyzed to know the difficulties in constructing passive voice into interrogative form. After that, questionnares are given to find out why the students get difficulties in constructing passive voice into interrogative form. Finally, the respondents who get the lowest score are interviewed and the lecturers are too.
According to the data that have been analyzed, triangulation is used as a technique to check the validity of qualitative research by comparing the data from documentation, questionnaires and interviews.

RESULTS AND DISCUSSION 1. Data from Students' Work
Before getting the result of students' work, the data of students' score from the lecturer are asked and selected five students who got low score of six classes to do the exercise. The research applies homogenous purposive sampling technique. After that, the students' works are collected as documentation. It is aimed to analyze the students' difficulties in changing passive voice into interrogative form. Four difficulties are found in grammatical errors such as difficulty in changing the position of subject and object, difficulty in using the auxiliary verb used, difficulty in determining the verb (past participle), and difficulty in deciding which sentence can be changed into passive or not (transitive and intransitive). The result of students' work is shown on table 4.1  I  II  III  IV   1  5  2  5  0  12  2  6  3  5  7  21  3  6  3  5  6  20  4  3  1  7,5  4  15,5  5  5  2  5  6  18  6  8  1  7,5  9  25,5  7  3  2  5  4  14  8  1  2  5  4  12  9  0  2  5  2  9  10  8  4  5  9  26  11  8  0  5  10  23  12  8  1  5  9  23  13  8  4  5  10  27  14  8  4  5  10  27  15  0  8  7,5  5  20,5  16  8  5  5  9  27  17  0  3  5  10  18  18  8  1  5  10  24  19  6  6  5  5  22  20  8  5  5  8  26  21  7  5  5  8  25  22  8  8  5  10  31  23  6  6  5  5  22  24  0  3  5  4  12  25  0  2  5  5  12  26  7  2  5  9  23  27  6  7  5  6  24  28  0  0  5  4  9  TOTA  L  141 92  147,  5   18  8  568,5 Note: R : Respondents I : Difficulty in changing position of subject or object II : Difficulty in using the auxiliary verb III : Difficulty in determining which sentence that can be changed into passive (transitive and intransitive verb) IV : Difficulty in deciding Verb 3/ past participle Based on the table 4.1, twenty-eight students as samples got low score of six classes It can be seem that students get some difficulties in changing passive voice in interrogative form. The writer analyzes four kinds of difficulties from their worksheet. Each categories have ten points of ten items. Therefore, if students are able to answer the whole items of four categories, they get 40 points. It becomes the highest score. The total of score is counted. The following is the result of analysis students' difficulties in the It can be shown that first, 141 total score (24.8%) in changing position of subject and object. Second, 92 total score (16.2%) in using the auxiliary verb. Third, 147.5 total score (25.9 %) in determining which is sentence that can be changed to passive voice (confusing with transitive verb and intransitive verb). Four, 188 total score (33.1 %) in choosing appropiate verb that used is past participle.
From the result above, the writer concludes that the highest difficulty in changing passive voice in interrogative form is in using the auxilliary verb with score 92 total score or 16.2 %. It is shown from their students' work, the scores are low, and only two students who get eight correct answers. For more detail information, the result of the students' work is described as following explanation:

a. Analysis the difficulty in changing position of subject and object
There are ten items that should be analyzed from students' work. The highest score in changing position of subject and object is eight scores of ten respondents; R#6, R#10, R#11, R#12, R#13, R#14, R#16, R#18, R#20, R#22. It means that they are able to change the position of subject and object when changing passive voice in interrogative form. Most students put the subject in the last of the sentence and put the object in beginning of the sentence. The writer predicts that they know the rule of passive voice therefore they are able to change the position of subject and object. Unfortunately, six respondents get zero score. They are R#9, R#15, R#17, R#24, R#25, and R#28. The zero score becomes the lowest score in changing the position of subject and object. It concludes, they are not able to change the position of subject and object when changing passive voice in interrogative form. The other scores such as seven scores of two respondents; R#21 and R#26, then six scores of five respondents; R#2, R#3, R#19, R#23, R#27. Next, five scores of two respondents; R#1 and R#5. Moreover, three scores of two respondents; R#4 and R#7. The last, one score of one respondent is R#8. b. Analysis the difficulty in determining the auxiliary verb that used There are four tenses of ten items that should be analyzed from students' work. They are three items about present perfect, two items about past perfect, three items about past progressive, and two items about present progressive. From each tenses, there are different auxiliaries of verb that must be analyzed. In addition, the highest difficulty score in this part is eight of two respondents, they are R#15 and R#22. It means that, they are able to determine the appropiate auxilliary verb that used in the sentence.
Moreover, the lowest difficulty score is zero of two respondents, they are R#11 and R#28. It defines that, from ten questions, they are not able to answer the whole items. Therefore, the writer presumes that they do not determine the appropriate auxiliary verb used in constructing passive voice into interrogative form. Furthermore, there are one respondent who get seven score, R#27. Then, two respondents with six scores, they are R#19 and R#23. Next, three respondents who get five scores, they are R#20, R#21, and R#16. In addition, there are three respondents with four scores, R#10, R#13, and R#14.
Henceforth, there are four respondents of three scores; R#2, R#3, R#17, and R#24. Besides, seven respondents who get two scores, they are R#1, R#5, R#7, R#8, R#9, R#25, and R#26. The last, only four respondents with one score, they are R#4, R#6, R#12, and R#18. In conclusion, most students are still confused to determine the appropriate auxiliary that used and still make mistake to put the position of to be (been and being) into the right place when constructing passive voice into interrogative form. c. Analysis the difficulty in determining which sentence can be changed into passive (transitive and intransitive verb) From ten items, there are two kinds of verb in passive sentence. They are eight items for the transitive verb. Meanwhile, two items for the intransitive verb. Based on the data above, three respondents with the score 7.5, the respondents are R#4, R#6, and R#15. Their scores become the highest score in this part. It seems that the students are able to differentiate which sentence that can be changed into passive or not and they know about transitive and intransitive verb.
Therefore, the writer assumes that they still get difficulties in determining which sentences that can be changed into passive voice and they are still confused with transitive and intransitive verb.

Analysis the difficulty in choosing the verb participle
In this part, the writer analyzes that the highest score is ten. There are six respondents with ten scores; they are R#11, R#13, R#14, R#17, R#18, and R#22. It explains that students are able to choose appropriate verb that used in changing passive voice in interrogative form. Then, there are four respondents with five scores. They are R#15 R#19, R#23, and R#25. Their scores become the mediocre score. It defines that they are not too confused to choose the past participle that used in changing passive voice in interrogative form.
Fortunately, only one respondent who gets the lowest score from the data above, the respondent is R#1 with zero score. It seems, the respondent is not able to choose the appropriate verb used in constructing passive voice into interrogative form. Other results that the writer got, there are five respondents with nine scores, and they are R#6, R#10, R#12, R#16, and R#26. Next, two respondents with eight scores; they are R#20, R#21. Then, one respondent who gets seven scores, there is R#2. Moreover, three respondents get six scores; they are R#3, R#5, and R#27. In addition, five respondents who get four scores; R#4, R#7, R#8, R#24, and R#28. Finally, there is one respondent with two scores; R#9. As the result, the students who get difficulty in choosing the verb 3 (past participle) are not too many, it is only eleven students

Data from Questionnaire
The questionnaire was distributed to the participants. It aims to get more information of students' difficulties in changing passive voice into interrogative form. There are three indicators in the questionnaire; they are students' abilities, the factors that influence students' difficulties and students' difficulties.

a. Students' Abilities
There are ten statements about students' abilities. Based on the data students' abilities on the table 4.3, it is shown that in the first statement, the respondents are asked whether they know about the characteristics of passive voice and interrogative form or not. There are 22 respondents (78.57%) admits that they know the characteristics about passive voice and six respondents (21.43%) do not know the characteristics of passive voice. It means that most respondents know about the characteristics of passive voice well.
Second, the respondents are asked whether they know about the pattern and the rules how to change passive voice in interrogative form correctly or not. The result is 12 respondents or 42.86% says that they know the pattern and the rules how to change passive voice in interrogative form correctly.
Unfortunately, 16 respondents or 57.14 % do not know it correctly. It explains that most respondents who know about the pattern and the rules how to change passive voice in interrogative form correctly.
The third statement, the writer asks the respondents about the ability to change passive voice in interrogative form. There are ten respondents (35.7%) confesses that they are able to change passive voice in interrogative form and 18 respondents (64.3%) are not able to change passive voice in interrogative form. It defines that many respondents still confused how to change passive voice in interrogative form.
Fourth, the statement "I know about past participle (V3)" is asked to respondents. Then, many respondents about 23 respondents (81.14%) states that they know about the verb in passive (past participle) and five respondents (17.86) do not know about past participle. It seems, the ability of knowing past participle is recognized by many students.
Fifth, 15 respondents (53.57%) answer that they know about pronoun used in changing passive voice in interrogative form but 13 respondents (46.43%) do not know about it. It can be concluded that more than a half of respondents know about the pronoun that used in changing passive voice in interrogative form.
Sixth, 21 respondents admit that they are able to differentiate the transitive and intransitive verb. Unfortunately, seven respondents are not able about it. It means that most respondents have recognized about the transitive and intransitive verb. Seventh, the writer analyzes that nine respondents who state that they know the kinds of passive voice however 19 respondents do not know about the kinds of passive voice. It is shown that many respondents who know and the rest respondents do not know about the kinds of passive voice.
Eighth, nobody is able to differentiate between stratal, dynamic and ditransitive verb. On the contrary, all respondents, 28 respondents (100%) say that they are not able to differentiate between stratal, dynamic and ditransitive verb. It seems that they do not know the differences between stratal, dynamic and ditransitive verb.
Nineth, all respondents about 28 respondents (100%) state that they know tenses; the continuous (present and past) and the perfect (present and past) and no one who say no. It means that the tenses; the continuous (present and past) and the perfect (present and past are easy to understand. Tenth, 18 respondents (64.29%) answer that they know to decide the auxiliary verb used in changing passive voice in interrogative form but ten respondents (35.71%) answer they do not about it . It explains that are able to decide the auxiliary verb used in changing passive voice in interrogative form.

b. The Factors that influence students'
difficulties 12 statements of three factors that influence students' difficulties are given. They are three statements about students' intelegence, six statements about students' learning style, and four statements about students' motivation. It is used to recognize the factors that influence the students' difficulties in changing passive voice in interrogative form.
For the statement number eleven, there are seven respondents (25%) agree that the lecturer's explanation is difficult to understand, meanwhile 21 respondents (75%) do not agree about it. It means that most of students have high intelegence and aptitude to understand the lecturer's explanation when learning passive voice and there is no problem with lecturer's explanation.
Next, 13 respondents ( 46.43%) state that they are hard to construct interrogative sentence and 15 respondents (53.57%) are not hard to construct interrogative sentence. It seems that changing interrogative sentence is hard for a some respondents. Then, 21 respondents (21%) admit that they are confused how to change passive voice into interrogative form and only seven respondents (25%) are not confused to change passive voice in interrogative form. It explains that a quarter of total respondents get difficulty to change passive voice in interrogative form.
Moreover, the result of statement number fourteen is 17 respondents (60.71%) said that they always record the important points and the examples of passive sentence but 11 respondents (39.29%) do not record it. It means that most respondent is visual learner and they record the point to make easier in learning passive voice. Then, 17 respondents (60.71%) read grammar book if the lecturer's explanation is difficult to understand and only 11 respondents (39.29%) do not do it. It defines that most of respondents are dominant visual learner and apply visual style like; read grammar book when the lecturer's explanation is hard.
Furthermore, the result of statement number sixteen is 14 respondents (50%) confess that they make a learning group to more undertand the lesson and 14 respondents (50%) also do not do it. It is shown that a half of total respondents. In addition, twenty seven respondents (96.43%) say that they always ask to their friends if the lecturer's explanation is difficult to understand whereas only one respondent (3.57%) says do not ask to friends. It means that almost respondents ask to their friends when the lecturer explanation is difficult to understand.
Afterwards, the result of statement number eighteen is 14 respondents (50%) always ask directly to lecturer if they do not understand about passive voice and fourteen respondents do not do it. It confesses that a half of total respondents agree with the statement and a half of total respondents do not agree. Next, three respondents (10.71%) join the course to increase the English ability especially in grammar and 25 respondents (25%) do not join course. It means that, almost respondents do not join course to increase the English ability especially in grammar.
According to the data obtained, 11 respondents (39.29%) are interested in learning Understanding English Structure and 17 respondents (60.71%) are not interested with that subject. It states that their internal motivation is low because more respondents do not interested in learning Understanding English Structure. In addition, 22 respondents (78.57%) admit that their parents and home atmosphere support them in learning English that provided some facilities and only six respondents (21.43%) do not admit it. It concludes that external motivation in family really influences for most respondents.
Henceforth, the result of statement number 22 is ten respondents answer "yes" that the campus atmosphere and facility do not support in learning English and 18 respondents (64.3%) answer "no" about it. It explains that external motivation in campus really influences for most respondents. At the last, 18 respondents (64.3%) state that the lecturer uses some interesting technique in teaching passive voice and ten respondents (35.7%) do not admit it. It means that external motivation from the lecturer also influences in learning passive voice.

c. Students' difficulties
In this part, seven statements consist of five kinds of students difficulties.
They are two statements about the characteristics of passive voice, two statements about determining the auxiliary verb, two statements about choosing diction, one statement about the using the tenses, and one statement about kinds of sentence. According to the data obtained, 14 respondents (50%) say that they get difficulty in changing passive sentence in interrogative form although they have known the pattern and 14 (50%) do not say it. It defines, a half of students still get difficulty in changing passive sentence in interrogative form although they have known the pattern.
Then, 17 respondents answer that they are hard to determine the subject and object position in changing passive voice in interrogative form as well as 11 respondents answer they are not hard no determine the subject and object. It is shown that many respondents still get difficulty in determining the subject and object in changing passive voice in interrogative form.
On the other hand, 16 respondents state that they are confused to determine the auxiliary verb that used when changing passive voice in interrogative form and 12 respondents do not state it. It explains that more than a half of total respondents get difficulty in determining the appropriate auxiliary verb that used when changing passive voice in interrogative form.
Afterwards, the result of the statement number 27 is a half of total respondents or 14 respondents (50%) confess, they are confused to decide the verb (past participle) when changing passive voice in interrogative form and 14 respondents (50%) are not confused to decide the verb (past participle). It means that still many respondents who get difficulty in deciding the appropriate verb (past participle) in changing passive voice in interrogative form.
Henceforth, twelve respondents (42.86%) claim that they get difficulty to determine the pronoun (objective pronoun) when changing passive voice in interrogative form and 16 respondents do not claim it. It concludes that they are able to determine the pronoun (objective pronoun) when changing passive voice in interrogative form.
Furthermore, 17 respondents (60.71%) argue that they get difficulty to change passive voice in interrogative form using tenses; the perfect (simple and past) and the continuous (simple and past), on the contrary 11 respondents (39.29%) do not get difficulty to change passive voice in interrogative form using certain tenses. It means that more than a half of total respondents still get difficulty to change passive voice in interrogative form using tenses.
Finally, 18 respondents answer that they are confused to determine which sentence can be formed into passive or not and ten respondents are not confused about it. It is shown that, most respondents are still confused to determine which sentence can be formed into passive or not.

Data from Interview a. Interview with the students
The last step in collecting the data is interview. five students from each classes are interviewed to get more information in analyzing students' difficulties in changing passive voice in interrogative form. Besides, it is used to assure students answer in questionnaire. There are ten questions of three categories, they are three questions of students' abilities and three questions of the factors that influenced students' difficulties and four questions of students' difficulties.
Here are the respondents' answers of interview: Unfortunately, there are three respondents who are doubt about tenses perfect (present and past) and continuous (present and past). It is supported by statement #R1 "Present perfect yang pake verb 1, past perfect yang pake verb 3, continuous pake to be + verb ing". [Present perfect uses verb 1, past uses verb 3, and continuous uses to be + verb ing].

2) The Factors that Influence Students' Difficulties
According to the result of interview, three items related with this category are given to the participants. For the result of questions number four, all respondents answer that they motivate their self in learning passive voice through their own ways as trying to learn individually, starting from their intend, doing some exercises, opening and learning more the lesson. It is proven by statement R#2 says Besides, internal factors also influence. It is stated with the statement #R5,"Yang paling mendukung itu berarti harus banyak googling, searching tentang passive voice, media juga, terus membeli buku yang berkaitan dengan structure khususnya passive voice". [The most thing that support in learning passive is more googling, searching about passive voice and media also influenced. Then, we buy some books and finds out sources that related with structure especially passive voice].

3) Students' Difficulties
In this category, four difficulties of the result of interview are analyzed. The following is the results of interview: First, the difficulty in changing position subject and object. Based on the data, the writer analyzes that all respondents; R#1, 2, 3, 4, and 5 agree that they know the pattern and they can change position subject and object According to the data obtained, two respondents agree that the action to make students more understand is the lecturer should be more active and clearer in teaching passive voice. It is proven by statement R#1 Neranginnya bener-bener jelas banget, jadi biar muridnya bener-bener ngerti dulu semua jangan yang satu ngerti yang lainnya yang ga ngerti ditinggalin, terus harus banyak latihan soal dan contoh-contoh juga [The lecturer should explain clearly to make students more understand the material, and do not ignore someone who has not understood yet. In addition, the lecturer should give exercises and examples. R#3 also argue] In addition, the lecturer should apply some interesting method to simplify the material, it is revealed by statement R#2 Yang pertama, dosen harus mensimplekan materinya agar lebih mudah dan mungkin kalau perlu membuat tahapatahapan agar si mahasiswa mudah mengerti, dari soalnya juga harus bertahap dari mudah-sedang-sukar".
[First, the lecturer should make the material easier to understand and need the sequence when explaining it. The exercises also should create sequentially from easy exercise until hard exercise] It is clear that all respondents hope the lecturer can convey the material clearer and use simple technique in teaching passive voice.

b. Interview with the lecturer
In this research, two lecturers are interviewed. Based on the result of interview, the lecturers said that some students are able to change passive voice in interrogative form and some students still get difficulties in changing passive voice in interrogative form. It is based on the students' ability to understand the lesson or their intelligence. It is proven with the statement R#2 It means that the lecturers get difficulty to teach the material of passive into interrogative form when the students cannot comprehend about positive passive form. Besides, the lecturer said that the most students get difficulty to determine appropriate auxiliary verb.
From those statements above explain that students are confused when directly changing passive in interrogative form, they should comprehend passive positive first, after that they are easy to change in interrogative form and they are still confused with auxiliary verb used that related with certain tenses and singular-plural.
According to the data obtained, the first lecturer mentions that she teaches passive voice with some strategies to make students easier to understand. It is proven with her statement [I usually apply the strategy to translate the sentence in Indonesian. It is used to make the students understand the meaning first….. If it does not work, I use plan B. I ask the students to change the active sentence into passive. For example, the car was not washed. Then I ask them where is to be, after they know it, I ask them to change in interrogative form. They only put to be at the beginning of the sentence and exchange the position to be and subject, it is easier] From those statements above, the writer concludes that the lecturers have tried to simplify the lesson and uses the simple technique to make students understand the lesson however still uses conventional method.

Discussion
The writer found that generally four kinds of students' difficulties have been known by the previous researcher. Actually they are able to change passive voice into interrogative form but they have many factors that influences their difficulties. In this part, the writer wants to prove the previous theory with the phenomenon nowday and she used the theory as her reference in conducting this reserach. It was line with the theory from Geoffrey (Anfan, 2013:14) states Most learners who learn English grammar about passive voice get difficulty in understanding the grammatical error like position of subject and object, determining the auxiliary verbs, also confusing to decide the verb/past participle. Then, getting problem in determining which sentence that can be transformed to passive voice.
Then for the causes, it is related with one of excerpt from the sources that become the theoritical foundation for this research.It was line of the theory of Benson, Lightbown and Spada (2001:67);(2003:51) "Students' difficulties are influenced by a variety of individual physicological variabels such as intelegence, aptitude, personality, learning style, motivation, affective state and belief".

Validity Checking
Validity checking is done by comparing the data from documentation, questionnaire, and interview. It is used to crosschecks all the data obtained and make sure the result of the paper.
Based on the result of students' work, most respondents still get four difficulties in changing passive voice in interrogative form. They are 141 total score (24.8%) in changing the position subject and object, 92 total score (16.2%) in determining the appropriate auxiliary verb , 147.5 total score (25.9 %) in determining the sentence that can be changed into passive and 188 score (33.1 %) in determining the verb participle. It means that most difficulty is in changing the auxiliary verb.
It is also proven from the result of questionnare that shows 16 respondents (57.14%) get difficult to determine the appropriate auxiliary verb that used and 12 respondents (42.86%) disagree with the statement. That statement is also admitted in the result of students' interview with #R4 and 5  [They are exactly wrong in to be. Mostly, They are confused in plural, sometimes they still use to be for singular however the subject is plural and their ability about tenses is less. They are confused to determine which we use is/are, was/were] From the data of three instuments, the writer summarizes that all the data is rellevant. All data have related each other.
In addition, the writer has analyzed that the most causes of this research come from internal factor such as intelligence and aptitude, personality and learning style as well as motivation. First, the intelligence and aptitude are faced in the result of questionnaire number one states "Saya mengetahui kalimat pasif dan kegunaannya". [I know the passive voice and the function]. The result is 22 respondents (78.57%) say yes. It defines that their ability to understand the material of passive is good enough. Unfortunately, it is not relevant with the result of students' work. It shows; 18 respondents cannot change the position subject and object, 20 respondents are confused to choose the appropriate auxiliary. In addition, seven respondents still get difficulty to determine verb participle and decide which sentence can be changed into passive.
The result of interview also proves that they know the passive but they do not too know the function of passive. It is described with statements #R2 and R#5 Passive sendiri yaitu lawannya dari kalimat aktif, passive voice adalah suatu kalimat yang merubah subjek menjadi objek, to be + verb 3 dan digunakan untuk merubah asalnya subjek menjadi objek [Passive is the opposite of active. Passive voice is a sentence construction that changes subject into object, to be + verb 3 and used to change the position of subject and object] The writer assumes that the students actually know the pattern of passive voice but they do not apply it when doing the exercises. They are lack of ability in changing passive voice in interrogative form.
Second, personality and learning style show in the result of questionnaire in statement number 17 "Saya selalu bertanya pada teman saya apabila penjelasan dari dosen sulit dipahami". [I always aask my friend if the lecturer's explanation is difficult to understand]. The result is almost a half of respondents (96.43%) argue yes. It is also mentioned with the statement R#2, 4, and 5 " Yang pertama tentu saya akan bertanya kepada kawan terdekat dulu, jika kawan tidak bisa menjelaskan baru minta penjelasan ke dosen yang mengajarkan". [The first is I am going to ask my classmates, if they cannot explain I am going to ask the lecturer].
It concludes that many respondents prefer asking to their friend than asking the lecturer. Therefore, they still get difficulties in changing passive sentence in interrogative form because they believe their friend than their lecturer. [Something that supports students in learning process is the lecturer itself. However, a good lecturer can convey the material properly and use some media to support it.] The lecturer also says like that. She says that she also gives the students encouragement to appreciate their effort in learning English especially passive voice. Here is her statement: Biasanya kalau saya setelah menerangkan saya kasih latihan misalnya sepuluh soal langsung dibahas hari itu juga terus saya tanya ke yang meriksa siapa saja betul semua jawabannya disebutkan namanya. Hal itu memotivasi anak-anak yang lain ok banyak juga yang dapat nilai sepuluh [After explaining the material, I usually give the students some exercises for example ten items; it should be done at that moment. Then, we crosscheck it together. After that, I ask to the students who crosscheck the right answer of the worksheet who get the highest score and mention the name. Next, I mention the name. It is used to motivate the others to do the exercises correctly and get a winner] From the statements above, it is showed that the students more pay attention with external motivation than internal motivation. In addition, the lecturer plays big role to make students understand in learning English. Actually, internal motivation is less because they are not interested in learning grammar.
After comparing all the data, the writer concludes that the internal factor is the most factor that influences students' difficulties. Consequently, they get difficulties in constructing passive voice into interrogative form. Henceforth, it is clear that each data from students' work, the result of questionnaire and interview are valid because they have relationship each other.

CONCLUSION
The research shows most respondents have four types of difficulties in changing passive voice in interrogative form. The difficulties are about grammatical error such as first, difficulty in changing the position of subject and object; second, difficulty in determining auxiliary verb used; third, difficulty in deciding which sentence can be changed into passive and the last, difficulty in choosing the verb participle. The most difficulty is in determining auxiliary verb that used. It is proven with three data; the result of students' work, questionnaire and interview. The students state that they still confused to choose to be and they often ignore about singular and plural material as well as less carefullness with tenses.
From those difficulties, the causes of students' difficulties in changing passive voice in interrogative form are also analyzed. There are two causes that can influence students' difficulties in changing passive voice in interrogative form, they are internal factors and external factors. For internal factors, there are three aspects, they are students' intellegence and aptitude, students' personality and learning style, as well as students' motivation. Then, external factors include the material, the facility and atmosphere, as well as the lecturer's explanation. As the result, the most causes that influence students' difficulties in constructing passive voice are from students' motivation of internal factor and from lecturer's explanation of external factor. It is shown with the data of questionnaire and the result of interview. The students claim that they know the pattern of passive voice but they are still confused to apply it when they do the exercises, they have less ability to change passive voice in interrogative form. However they have high motivation from their parents and lecturer. Unfortunately, they have less motivation of themselves because they are not interested in learning grammar. In addition, they do not have problem with lecturer's explanation because the lecturer encourages them to make students easier to understand with some simple techniques that used in learning process, then the facility and atmosphere also support them in learning. Finally, their friends also influence the students however it does not make any change because their internal motivation is less.