找英语的所有时态以及每个时态的结构（be going to.)

时态 形式 关键词一般现在时 am,is ,are,do,does Every day..,often,always,sometimes,seldom,on Sundays一般过去时 Was,were,did Yesterday,...ago,last..,in 1980,the other day,five minutes later,after three d...