情態動詞+have+動詞過去分詞 * 表達過去事實 * 表達推測的含義（但助動詞should除外） ``` He can/could have arrived.他可能已經到了。（可能性次之） He may/might have arrived.他可能已經到了。（可能性最小） He must have arrived. 他準是已經到了。（可能性最大） ``` * should+have+p.p 本應該··· ``` He should have arrived.他本來應該已經到了。 They should have finished the work.他們本來應該已經完成這個工作了。 ``` * needn't+have+p.p 本不需要··· ``` You needn't have done so.你本不需要那么做的。 ``` * must+have+p.p 準是已經··· ``` He must have arrived. ``` * can't+have+p.p 不可能已經··· ``` He can't have arrived. ```