1) since +过去一个时间点 (如具体的年、月、日期、钟点、1980, last month, half past six)。 I have been here since 1989. 2) since +一段时间+ agpostgraduate;adj.大学毕业后的,大学研究院的;n.研究生;参考例句:I didn't put down that I had postgraduate degree.我没有写上我有硕士学位。 After college,Mary hopes to do postgraduate work in law school.大学毕业后, 玛丽想在法学院从事研究工作。