Abstract:
This study aimed at analyzing the students' performance in grammar when writing composition in the tertiary level, it also aimed at investigating the problems that face the students when they write compositions and suggest solutions in order to overcome these problems.
The study assumed that students in the tertiary level lack the knowledge of the correct use of verb as well as their inability to write good and coherent paragraph in addition to their inability to use parts of speech appropriately, then these assumptions are tested via the suitable tool (the test) in the form of composition which was given to the students of English language in the second level, College of Education at Sudan University of Science and Technology. After analyzing the students' performance the study has come out with the following results:
1. In using verbs, errors are committed in subject verb agreement particularly in present simple tense.
2. Regarding the modal auxiliaries, almost all the students tend to omit auxiliaries from the structure in spite of their obligatory involvement, while other students tend to use auxiliaries even i f they are not needed.
3. Errors are also committed in the use of prepositions. One could also identify types of errors committed by the students who have written the texts. these are singular plural agreement, word order, the inappropriate use of modifier, the use of verb as a modifier or to replace the noun, and the use of modifiers where they are not needed as well as the use of comparative adjectives as modifiers.
on the light of the results above the study recommends the followings:
1. Students should be aware of the use of verbs and tenses as well.
2. teachers should observe continuously the students' performance in writing and especially to their use of parts of speech in general.
3. Teachers should follow their students instructionally when writing.
4. Teachers should deliver sufficient exercises on tenses, modal auxiliaries, prepositions, relative pronouns, and noun modifiers.
