lesson 15 　情態(tài)動詞(二)

　　內 容 提 要

　　情態(tài)動詞有can(能)，may(可以)，must(必須)，have to(不得不)，ought to(應該)，dare(敢)，used to(過去經(jīng)常)，had better(最好)，would rather(寧愿)。在肯定句中它們后邊都要接 動詞原形 .在否定句中，can，may，must和dare后邊加not;have to和ought to分別在have和ought后加not;used to的否定式可用used not to，也可用didn't use to，但后者用得較多;had better和would rather的否定式分別是had better not和would rather not.這些情態(tài)動詞與現(xiàn)在完成時連用在某種意義上有一定的虛擬性。

　　情態(tài)動詞與完成時的使用

　　一、must+have+�睧D分詞：用于肯定句，表示對過去情況的一種肯定推測，表示“肯定，一定”

　　1) It around nine o'clock when I drove back home because it was already dark.

　　[A] had to be [B] must have been [C] was to be [D] must be

　　2) John's score on the test is the highest in the class;

　　[A] he should study last night

　　[B] he should have studied last night

　　[C] he must have studied last night

　　[D] he must had to study last night

　　3) After searching [A] for evidence in the house，the police concluded [B] that the thief must have come in [C] through the window and stole [D] the silver while the family was asleep.

　　二、may (might)+have+��ED分詞：用于肯定句和否定句，表示對已發(fā)生事情的不肯定的推測，相當于“可能，大概，”其中might較may 語氣更弱，把握更小

　　She might have gone to see her doctor last week， but I am not sure.

　　上星期或許她去看醫(yī)生了，但我不敢肯定。

　　Don't worry， your husband may not have been hurt seriously.

　　別急，你丈夫也許傷得不厲害。

　　三、should(ought to)+have+��ED分詞：肯定句表示過去本應發(fā)生的事卻沒有發(fā)生;否定句表示已發(fā)生了本不該發(fā)生的事。前者可譯為“本應，”后者為“本不該”

　　You should have apologized to her for not soon replying to the letter. 你本應向她道歉，說明為什么沒能及時回信。(可你沒這么做)

　　4) You yesterday if you were really serious about your work.

　　[A] ought to come[B] ought to be coming[C] ought to have come[D] ought have come

　　四、can(not) +have+�睧D分詞

　　He is an hour late —— He can have been delayed by fog. Of course，that's a possibility.他遲到了1小時，可能因為大霧而耽擱了。當然這只是可能性問題。

　　The poem can not have been written by her since she was only five years old then.這詩不可能是她寫的，因為她那時才5歲。

　　五、“could+have+��ED分詞”有時用于表示過去的時間，說明某事可能或不可能已發(fā)生;有時可表示過去本來可以做某事，但卻未做

　　I simply can't understand how he could have made such a mistake. 我簡直不明白他怎么會犯那樣的錯誤。

　　He walked there，but he could have taken a taxi. 他走著去了，可當時完全可以坐出租。

　　“couldn't+have+�睧D分詞”還表示無論如何也不可能或沒有做到

　　I couldn't have called you. I wasn't near a telephone. 反正我也不可能給你打電話，我附近沒有電話。

　　5) “We didn't see him at the lecture yesterday.”“He it.”

　　[A] mustn't attended[B] couldn't have attended[C] would have not attended[D] needn't have attended

　　六、needn't+have+��ED分詞：表示對過去不必做的事情卻做了，可譯為“其實不必”

　　6) You all these parcels yourself.The shop would have delivered them if you had asked a shop assistant.

　　[A] didn't need to carry[B] needn't have carried[C] needn't carry[D] didn't need carry

　　七、used to 表示過去的習慣動作或狀態(tài)，現(xiàn)在已不存在，在否定陳述句中，一般用didn't use to，也可用used not to;在疑問句中用“Did…use to”。used to還可never，often，always等連用。注意used to與be used to的不同，后者表示be accustomed to “習慣于某種狀態(tài)”，而且跟接名詞或�睮NG形式，而used to后接動詞原形，試比較

　　He used to drink. 表示“他過去經(jīng)常喝酒”而現(xiàn)在不喝了。

　　He is used to wine (He is used to drinking wine) at each meal.

　　表示“他現(xiàn)在已養(yǎng)成習慣，每頓飯喝點葡萄酒。”

　　八、had better表示“最好……”，后接動詞原形，其否定式為had better not+動詞原形

　　You had better not follow his behavior. 你最好不要學他。

　　九、would rather 意思是“寧愿”，表示選擇。它有兩種用法，一是在肯定句中后邊直接跟動詞原形，其否定句是在would rather 后加not，即 would rather not+動詞原形;二是它后邊可以跟接從句，該從句的謂語動詞用一般過去式表示虛擬語氣。由于would rather表示選擇，它后邊可跟接than

　　She would rather sleep than talk rubbish. 她寧愿睡不愿閑聊。

　　7) “Did you criticize him for his mistakes?”——“Yes，but it.”

　　[A] I'd rather not do[B] I'd rather not doing[C] I'd rather not have done[D] I'd rather not did

　　[注] would rather和had rather都表示“寧愿”，在用法上也沒有區(qū)別。但如果說would rather與had rather完全一樣(Longman Dictionary of Comtemporary English 如是說)，這一說法有爭議。其實had rather在現(xiàn)代標準英語中幾乎已經(jīng)不用了。這對我們考試來說是比較重要的，因為一般考題作為標準英語是不用had rather的。

　　十、例題解析

　　1) B為正確答案。2) C為正確答案。

　　3) D錯。改為stolen.這里C處和D處是并列的謂語，D處相當于must have stolen.

　　4) C為正確答案。5) B為正確答案。6) B為正確答案。7) C為正確答案。

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