如题所述
第1个回答 2011-02-19
need have done 。。。本人才疏学浅，没见过这种说法，通常是need to be done，表示需要被完成。如：All the housework needs to be done today. (今天需要完成所有家务。)
must have done肯定猜测语气，表示一定已经完成了。如：He must have finished the housework.（他肯定已经完成家务了。）
could have done 表示本可能已经完成某件事，常表示结果与事实相反。can have done 不常见。如：He could have finished the housework if he didn't watch the basketball games.（如果他不看篮球赛，本应该已完成家务了。）
should have done，应该已经完成某事，这个“应该”不是指推测，而是指理论上的，或义务上的。如：According to the cookbook，the cake should have been baked well now. (根据菜谱，蛋糕应该已经被烤好了。)
must have done肯定猜测语气，表示一定已经完成了。如：He must have finished the housework.（他肯定已经完成家务了。）
could have done 表示本可能已经完成某件事，常表示结果与事实相反。can have done 不常见。如：He could have finished the housework if he didn't watch the basketball games.（如果他不看篮球赛，本应该已完成家务了。）
should have done，应该已经完成某事，这个“应该”不是指推测，而是指理论上的，或义务上的。如：According to the cookbook，the cake should have been baked well now. (根据菜谱，蛋糕应该已经被烤好了。)
