142. MELT Journal, Vol 3, Issue 2, December 2018 ISSN:2528-0287 STUDENTS’ ERRORS IN USING MODALS Enni Maisaroh English Education Department Universitas Potensi Utama, Medan, North Sumatera E-mail: eni.antbee@yahoo.com Abstract: This study deals with the students’ errors in using modals of Can, May and Must. There were 25 students chosen as the sample who were asked to write compositions containing the modals. There were errors found in the writings which were categorized into 10 types according to the use of the modals. Type 1 (modal + simple infinitive to) is the dominant errors while Type 5 ( modal + pronoun) is the fewest. In all, there were 52 errors made in 192 modals used. Therefore, the percentage of the errors is 27%. This implies that the students could use the modals quite well. The second most difficult in the compositions is Must (34.92%) while according to their responses in the questionnaire the most difficult modal verb is May (48%) the causes of the errors were that the students lacked the knowledge of the uses; They seldom, practiced the use of the modals in compositions , and applied translation approach to use the modals in their writings. It is suggested that they be taught the pattern modal + simple infinitive to because this is the most common error. Keywords: errors, modals, compositions, questionnaire INTRODUCTION Grammar is the most important part of language for anyone which should be first understood before being able to construct sentences. Rules based on the grammar of a language are used to express a certain idea represented in a sentence. By understanding the grammatical rules, the sentences can be arranged to produce the desired meaning. For instance, the same words in these two, sentences: 1) The man teaches the woman , and 2) The woman teaches the man, produce a different meaning. In the first sentence, “the man” takes the role of “the teacher” while in the second one, it is “the woman” who acts like a teacher. This difference is due to the fact that the grammatical rules of English have their own systems or syntactic rules. It is undeniable that in order for one to master English, its grammar must be well understood first. However, the grammar itself covers many aspects. The eight parts of speech such as “noun, pronoun, verb, adverb, adjective, preposition, conjunction, and interjection” have their own syntactic rules which allow for a variety of meanings to be expressed. Learning how these parts of speech are used in everyday situation provides an insight into the problems of learning and understanding English as a foreign language. It is clear that