<正> 一、若主句的谓语动词是现在时态,从句的谓语动词是非持续性动词,则从句的动词只能用一般过去式: 1.It is(or has been}two months since he fell ill.(不能用has or hadfallen ill)(自)他生病(以来)已有两个月了。 2.It has been(or is)about ten minutes since the film began.(不能用hasor had begun)(自)电影开演(到现在)大约已有10分钟了。二、若主句和从句的谓语动词都是过去时态,从句的谓语动词又是非持续性动词,主句和从句的谓语动词时态搭配则有四种情况:
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