第1个回答 2017-04-01
"since"的5种用法:
1since+过去某时间点[指具体的年,月,日,时,星期几等] eg:he has beeb here since 1999
2.since+一段时间+ago eg:ha has been here since 5years ago
3.since+一般过去时的从句 eg:many things have changed since you left
4.it is/has been +一段时间+since+从句 eg: it is 2 years since i came here
5.it is +some time+since+从句 表示"自从...以来,已经...时间了"本回答被网友采纳