在職mba英語語法句型之情態動詞本身有語義, 表示說話人的語氣或情態, 但語義不完整, 不能單獨作謂語動詞, 一般只能與動詞原形一起構成謂語動詞。現就考試中出現頻率高的情態動詞及其用法作些說明:

    一、must

　　與must有關的題型經常與其后面應跟什么時態有關. 在有must的句中, 常表示說話人在進行依據較充分的推測。至于用哪些時態, 則有兩個參考標準: 句中的時間狀語和句間的關系。

　　You look so sleepy. You must have sat up late last night.

　　你看上去這么困倦, 昨晚一定睡得很晚。

　　I mailed that letter a week ago. He must have received it.

　　我一周前就發出了那封信, 想必他一定收到了。

　　must + have + -ed分詞: 用于肯定句, 表示對過去情況的推測, 意為“肯定, 一定”。

　　You had only a little egg at breakfast today. You must be hungry now.

　　Must 加動詞原形的進行式, 表示對現在發生動作和事物的猜測, 有“一定, 準是”的意思。

　　其他情態動詞如may (might), should (ought to), can(could), need的用法分別如下:

　　二、may(might)

　　may(might) + have + -ed 分詞: 用于肯定句和其他否定句, 表示對已發生事情的不肯定的推測, 意為“可能, 大概”, 其中might較may語氣更弱, 把握更小。

　　They may have derived inspiration from these words.

　　他們可能從這些話語中獲得了靈感。

　　Our manager may (might) have gone to Guangzhuo attending Spring Fair there last week.

　　我們經理可能已于上周去廣州參加春交會了。

　　三、should

　　除了其一般的用法以外, should 也表示說話人的感情如憤怒, 驚奇, 失望等。

　　I am sorry that he should be so stubborn.

　　他居然如此固執, 我對此感到很抱歉。

　　Why should I go there while she stays home?

　　為什么我得去那兒, 而她卻能呆在家里?

　　should(ought to) + have+ -ed 分詞句型: 指過去的事情。如果是肯定句, 表示過去本應發生的事卻沒有發生, 含“遺憾、責備、建議或指正”等意味; 如果是否定句則表示已發生了本不該發生的事。

　　You should have told him the paint on that seat is wet.

　　你本應告訴他座位上的油漆未干。

　　They should’t have left so soon.

　　他們不該這么早就離開。

　　四、can(could)

　　用于否定或疑問句中, 后面跟動詞原形的完成式時, 表示對過去發生的事件的“懷疑或不肯定”。could 比can更表示說話人語氣的不肯定。

　　Nobody could have foreseen all this.

　　當時無人能預見到所有這一切。

　　It couldn’t have been Mr. Smith. He has gone to China.

　　不太可能是史密斯先生。他已去了中國。

　　五、need

　　needn’t + have + -ed分詞: 表示過去做了但不必做的事情, 意為“其實不必”。

　　You needn’t have walked up; you could have taken the lift.

　　你本不必跑上來, 你本來可以乘電梯的。

　　You needn’t have watered the vegetables, as it is going to rain.

　　你本不必給蔬菜澆水, 因為天要下雨了。

　　Exercises 11 Choose the best answer to complete the following sentences:

　　1. The room is such a terrible mess. It ____cleaned as the landlady said.

　　A. mustn’t be B. mustn’t have been

　　C. can’t be D. can’t have been

　　2. With her hands so full, she____to the concert last night.

[FS:PAGE] 　　A.wouldn’t go B. oughtn’t to go

　　C. shouldn’t have gone D. mustn’t go

　　3. We ____ her letter last week. We don’t know what has happened to her.

　　A. must receive B. must have received

　　C. ought to receive D. ought to have received

　　4. There ____be an open window somewhere, I can feel cold air coming in.

　　A. should B. must

　　C. seem D. ought

　　5. If the doctor had been available, the patient _______.

　　A. could not have died B. should not have died

　　C. wouldn’t have died D. would not die

　　6. Since it’s snowing so hard, we____at home.

　　A. had better staying B. should stay

　　C. had better to stay D. might as well stay

　　7. The wine bottle is nearly empty; you ____ a lot.

　　A. may have drunk B. ought to have drunk

　　C. must have drunk D. could have drunk

　　8. According to western culture, you ____ask a woman her age; it is impolite.

　　A. needn’t(不必) B. don’t have to

　　C. mustn’t (不可以) D. have not got to

　　9. She didn’t know you were here; otherwise she ____ to meet you.

　　A. would have come B. had come

　　C. must have come D. would come

　　10. I wish you____a little longer.

　　A. would stay B. will stay

　　C. would have stayed D. will have stayed