情態動詞表推測的常考考點

（摘自《第二課堂》）

一、考查百分之百可能性的推測

英語中表示百分之百的可能性，用情態動詞must，意思是“一定”“肯定”，所作出的推測幾乎接近事實。如：

Now sit down and make yourself comfortable. You must be very tired. 現在坐下來，讓自己舒服些，你一定很累了。

若是要對過去情況作肯定推測，則要用“must+完成式”。如：

He must have come this way; here are his footprints. 他一定是走這條路來的，這里還有他的腳印呢。

His only explanation was that he must have brought them home in order to continue his work. 他唯一的解釋是，自己想必是為了繼續工作而把它們帶回家了。

【真題驗證】（答案分別為DB）

1. Harry is feeling uncomfortable. He ______ too much at the party last night. (2013遼寧卷)

A. could drink           B. should drink          C. would have drunk  D. must have drunk

2. Since nobody gave him any help, he ______ have done the research on his own. (2013課標卷II)

A. can                      B. must                     C. would                   D. need

二、考查具有較大的可能性的推測

表示可能性較大的情態動詞主要有may, should, ought to，它們大致相當于漢語的“可能”“應該”“按理會”。如：

You could try the drugstore, but it may well be closed by now. 你可以到雜貨店去試試，但現在很可能關門了。

I wonder what’s happened to Annie. She should be here by now. 不知安妮出什么事了，到現在她應該到了。

若是要對過去情況作較大可能性的推測，則要用“may (should, ought to)+完成式”。如：

I should have gone this morning but I was feeling a bit ill. 今天早晨我本應該走的，但是我覺得有點不舒服。

【真題驗證】（該知識點近兩年高考考得比較少，主要以干擾項形式出現；答案均為B）

1. When I was a child, I ______ watch TV whenever I wanted to. (2013江西卷)

A. should                  B. could                    C. must                     D. need

2. It ______ be the vocabulary that caused you the problem in the exercise because you know a lot of words. (2013安徽卷)

A. may                     B. couldn’t                C. should                  D. needn’t

三、考查具有較小可能性的推測

在所有表示推測的情態動詞中，might和could所表示的可能性最小，由于它們的語氣較委婉，較不確定，所以往往相當于漢語的“可能”“也許”“說不定”等。如：

I might come and visit you in America next year, if I can save enough money. 如果我能存在足夠的錢，我明年可能來美國探望你。

My wife's in hospital—our baby could arrive at any time. 我妻子住進了醫院——我們的小寶寶隨時都可能出生。

若是要對過去情況作較大可能性的推測，則要用“might (could)+完成式”。如：

He drove so fast; he might have had a bad accident. 駕駛那么快，他可能會出車禍的。

【真題驗證】（答案分別為ADD）

1. —You needn’t take an umbrella. It isn’t going to rain.

—Well, I don’t know. It ______ do. (2013北京卷)

A. might                   B. need                     C. would                   D. should

2. —What are you doing this Saturday?

—I’m not sure, but I ______ go to the Rolling Stones concert. (2013重慶卷)

A. must                    B. would                   C. should                  D. might

3. I ______ myself more —it was a perfect day. (2013浙江卷)

A. shouldn’t have enjoyed                          B. needn’t have enjoyed  

C. wouldn’t have enjoyed                           D. couldn’t have enjoyed

四、考查理論上的可能性

表示理論上的可能性（即理論上有可能但實際上未必會發生的情況），英語通常是用can，且可以用于肯定句中。如：

Even an experienced climber can get into trouble. 哪怕是有經驗的登山者也可能陷入困境。

Noise can be quite a problem when you’re living in a flat. 住在公寓里，噪音可能是一個不小的問題。

若不是表示理論上的可能性，則can只用于否定句或疑問句，而不用于肯定句。如：

If winter comes, can spring be far behind? 冬天來了，春天還會遠嗎?

You’ll see the building on your left. You can’t miss it. 那棟建筑在你的左手邊。你一定不會看不到的。

同樣地，若要對過去情況作推測，則要用“can+完成式”。如：

From her knowledge of Douglas’s habits, she feels sure that the attacker can’t have been Douglas. 根據她對道格拉斯生活習慣的了解，她敢肯定襲擊者不可能是道格拉斯。

【真題驗證】（答案分別為BA）

1. I______ thank you too much for all your help to my son while we were away from home. (2012陜西卷)

A. won’t                  B. can’t                 C. can                 D. will 

2. —Why are your eyes so red? You ______ have slept well last night.

—Yeah, I stayed up late writing a report. (2013四川卷)

A. can’t                    B. mustn’t                 C. needn’t                 D. won’t