11.13 since的四种用法 |
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+ago I have been here since five months ago. 3)since+从句 Great changes have taken place since you left. Considerable time has elapsed since we have been here. 4)It is+一段时间+since从句 It is two years since I became a postgraduate student. |