作业帮 > 英语 > 作业

they (know)each other since they (begin) to work in that fac

来源:学生作业帮 编辑:大师作文网作业帮 分类:英语作业 时间:2024/09/29 19:27:57
they (know)each other since they (begin) to work in that factry.
请问正确时态是什么呢?1.knew.began.2.have known.began.3.had konwn.began.
they (know)each other since they (begin) to work in that fac
2
在这里since从句后面谓语动词用一般过去时,主句用现在完成时
这里有一些例句,可以看一下然后理解一下
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.