摘要：keyword: MASTERY, SECOND YEAR, SOCIAL SCIENCESABSTRACT :Prepositions are a part of English Grammar that student learns at School, courseplace, or University, which help them to present ideas. The aim of this study isto compare students mastery between the Second year of natural and socialssciences students at SMUN 1 Citeureup in using prepositions of time: In, On,and at. To conduct this research paper, the writer uses field research by doing observation and administering a test to the second tear of natural and social sciences students at SMUN 1 Citeureup. The result of this analysis is themastery between the Second year of natural and social sciences students atSMUN 1 Citeureup is same because they are in same level; even the sciencesstudents had better score.
