since一般后面跟什么时态

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/12 08:52:27
since一般后面跟什么时态

since一般后面跟什么时态
since一般后面跟什么时态

since一般后面跟什么时态
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).例如:
I have been here since 1989. 1989起,我一直在这儿.
2)since +一段时间+ ago.例如:
I have been here since five months ago. 我在这儿,已经有五个月了.
3)since +从句.例如:
Great changes have taken place since you left. 你走后,变化可大了.
Great changes have taken place since we were here. 我们走后,变化可大了.
4)It is +一段时间+ since从句.例如:
It is two years since I became a postgraduate student. 我考上研究生有两年了.

完成时