★一般现在时:
often,usually,always,sometimes,never,seldom,every week/day/year/month...,once a week,on Sundays
★一般过去时：
ago,yesterday,the day before yesterday,last week/year/night/month...,in 1989,just now,at the age of five,one day,ago,long ago,once upon a time,then(那时),on that day,
★现在进行时：
now,at this time,these days,Listen!Look!at this moment/time
★过去进行时：
at this time yesterday,at that time或"when + 一般过去时从句",at 1:00 last night
★现在完成时：
recently,recent years,these days/years,lately,since,for + 时段,in the past few years,ever since,in the last five months,up to now,since then,so far,ever,never,yet,lately,once,twice,three/four times...,already,before,just.
★过去完成时：
before,by the end of last year/term/month...
★一般将来时：
tomorrow,next day/week/month/year...,soon,in a few minutes,by...,the day after tomorrow,in the future
★过去将来时：
the next day/morning/year...,
the following month/week...
