1.一般过去时:lastyear(month,week,century),yesterday,in1988,3yearsago...
2.现在完成时态:since1999,since3yearsago,fortwomonths,for3hours...,yet,ever,never...;
3.现在进行时:now,atthemoment;
4.将来时:in2010,inthefuture,intwoyears,inthreeweeks...;
5.一般现在时:常用的频度副词always,usually,often,sometimes,seldom,never等;
6.将来完成时:bytheendof+将来时间,by+将来时间;
7.过去完成时:bytheendof+过去时间;
8..