摘要：The aims of this research is to reveal the integration of vocabulary and effective sentence mastery against the students of English department of Faculty of Education and Teachers Training UIN North Sumatra’s argumentative writing skills.This research uses a quantitative approach.The populations are students of English department of 6 classes.The samples in this result are students of class II.By using cluster random sampling,it was obtained a sample of 140 students.The instrument used is a test.These results indicate that: (1) vocabulary mastery contributed positively and significantly to the argumentative essay writing skills of students.The amount of contribution is 18.4%;(2) Effective sentence mastery contribute positively and significantly to the argumentative essay writing skills of students.The amount of contribution is 11.7%;(3) The mastery of vocabulary and mastery of effective sentences contributed positively and significantly to the argumentative essay writing skills of students.The contribution is 26.5%;(4) mastering vocabulary to effectively contribute by 16.39% against the argumentative essay writing skills of students;(5) The mastery effective sentence effectively contribute 13.11% against the argumentative essay writing skills of students.Based on the results of this study,it was concluded that the vocabulary and effective sentences mastery are the two factors that influence the argumentative essay writing skills of students.
