since的用法时态

sce的用法时态是怎样的呢？下面就让我们一起来了解一下吧

sce作为副词形式一般用于现在完成时或过去完成时，作为介词形式一般用于现在完成时或过去完成时。

用法

1、sce+过去一个时间点（比如具体的年、月、日期、钟点等）

例I have been here sce 1990.

2、sce+一段时间+ago

例I have been here sce six months ago.

3、sce+从句

例Great changes have taken place sce you left.

4、It is+一段时间+sce从句

例It is one years sce I became a postgraduate student.