72. I couldn't have won the award without your assistance.
點(diǎn)睛
couldn't have won意為“本來(lái)不會(huì)贏”，是虛擬語(yǔ)氣的一種，表示對(duì)過(guò)去情況的假設(shè)。
考點(diǎn)歸納
“情態(tài)動(dòng)詞＋現(xiàn)在完成時(shí)”句型的用法很多。如：
must have＋done sth. 表示對(duì)過(guò)去可能發(fā)生的事情的推測(cè)，意為“肯定”。如：
Mary has gone to work, but her bicycle is still here. She must have gone by bus. 瑪麗已經(jīng)去上班了，但是她的自行車(chē)還在這兒。她一定是坐公共汽車(chē)去的。
would like to have done sth. 意為“本打算做某事”。如：
I would like to have read the article, but I was very busy then. 我本來(lái)想讀一讀那篇文章，但是當(dāng)時(shí)太忙了。
needn't have done sth. 意為“本沒(méi)必要做某事”。如：
I dressed very warmly for the trip, but I needn't have done so. The weather was hot. 為了旅行，我穿得很暖和，但是其實(shí)沒(méi)有必要穿這么多。天氣比較熱。
ought to/should have done sth. 表示“本應(yīng)該做某事，而事實(shí)上并沒(méi)有做”。否定句表示“不該做某事而做了”。如：
1) You ought to have been more careful in this experiment. 在做這個(gè)試驗(yàn)的時(shí)候，你本應(yīng)該更細(xì)心一些。
2) He ought not to have thrown the old clothes away. 他本不該把那些舊衣服扔了。
