现在完成时属于现在时范围，故不能和过去的时间状语连用。如：yesterday,last Sunday,in1990,three years ago等。但是，在强调动作产生的后果和影响时，可以和一些表示不确定的时间状语连用。a. 用副词already和yet。already一般用于肯定句中，yet一般用于否定句和 疑问句中。如：We have already finished our homework.我们已完成作业了。They haven't finished their homework yet.他们还没有完成作业。b.用ever 和never。多用于否定或疑问句中，表示“曾经”或“从未“等。 如：-Have you ever been to the Great Wall?你曾经去过长城吗？-I have never been to the Great Wall.我从未去过长城。c.用表示到说话为止的过去时间状语，如just,before,up to now,the past few years等。例如：I have seen her before,but I can not remember where.我以前见过她，但记不起在哪里见过。He has been there three times the last few days.近几年他去过那里三次了。d.用包括“现在”在内的时间状语，如：now,today,this morning(month,year,term)等。例如：-Have you met him today?-No,I haven't.今天你见过他吗？我 没有。How many times have you been there this year?今年你去过那里多少次？