1、一般现在时:always,usually,often,sometimes,seldom,rarely,never, every day等。
2、一般过去时:last week four years ago before等。
3、一般将来时:tomorrow,tomorrow morning,the day after tomorrow,the day after next,the year after next等。
4、现在进行时:now,these days等。
5、过去进行时:this time yesterday,this time last Friday,in those days等。
6、现在完成时:ever since then, for three days等。
7、过去完成时:by then by the end of last term等。