Grammatical Errors Made by The Eleventh Grade Students in English Argumentative Writing

Grammatical errors that the English learners make in language learning are difficult to be avoided. To reduce those errors the learners should pay more attention in mastering grammar so it will not be fossilized in their minds. This paper aims at investigating grammatical error made by Eleventh Grade Students in English argumentative writing. This study is a descriptive qualitative by collecting data from students of Saint Hendrikus Senior High School writing test. The result shows that the course students with additional English Course do not make many errors in argumentative essay rather than another group. However, the frequency of the error is not too wide in every item between two groups. The misuse of using tense has almost the same frequency; 60% and 57% between two groups and it happened because the less comprehension of using adverb of time in a sentence. The less error happened only on using gerund 0% and