2、uestshadleftwhenhearrivedattheparty.当他到达晚会时,他发现大多数客人已经离开了。2.过去完成时还可表示过去某一时刻之前发生的动作或状态持续到过去某个时间或持续下去,常与for,since等词连用。例:WhenJackarrived,Maryhadbeenawayforalmostanhour.当杰克到时,玛丽已经离开快一个小时了。【实战演练】用所给词的适当形式填空。1. When I got there the bus _________ (go).2. By the
3、 time I got to class, the teacher___________(start) teaching.3. We _____________ (learn) over 1,000 wordsbytheend of last term.4. I ___________ (clean) the room before hearrived here.hadgonehadstartedhadlearnthadcleanedbythetime的用法bythetime意为“到……时候(为止)”,