你了解“情态动词+完成体”用法吗？

南昌十九中  宋焘

“情态动词+完成体”结构在英语中表达说话人的语气、情感等，是一项很重要的用法，学生对此用法要有一个全面透彻的认识和理解。

一、Must +完成体

must +完成体表示对已经发生事情的肯定推测,意为”一定已经”, “准是已经”。一般只用于肯定句，其否定形式用can’t have done 。例如：

１．Where is my key? I must have lost it.

２．Her father thought she must have met a foreigner.

二、Can +完成体

can +完成体表示对过去时间内可能发生事情的猜测或想象，推测过去某种动作“可能”发生了，多用于否定句或疑问句，表示对过去事情的怀疑和不肯定，其推断的语气很强。常译为“很可能……了”、“不可能……”、“……..可能吗？”例如：

1．He can’t have written this letter 这封信不可能是他写的

2．Can your teacher have forgotten your name ?你的老师会忘记你的名字吗？（意指老师不可能忘记。）

三、may +完成体

may +不定式的完成体表示对过去事物的怀疑或猜测，推测某事在过去可能发生了，表示“可能了”，“也许了”。例如：

1．You may have read about the news in the newspaper.

2．He may have gone to the hospital.

四、needn’t ＋完成体

needn’t ＋不定式的完成体表示做了不必要做的事情，意为“本可不必”，往往含有轻微的责备和抱怨。例如：

１．    You needn’t have taken a taxi , for it wasn’t such a long way.

２．    She needn’t have gone to the airport yesterday.

五、should ＋完成体

should ＋不定式的完成体表示该做某事而实际上未做，含有责备意味，意为“本该”，其否定式则表示做了不该做的事，意为“本不该”。

１．Jenny should have kept her word. I wonder why she changed her mind.

２． We shouldn’t have waited for her because she never came.

六、ought to＋完成体

ought to ＋不定式的完成体表示过去该做的事情而没有做，含有责备的意思，语气较should强，意为“本来应该”；其否定式“ought not to +不定式的完成体”表示“本不该….而做了”。例如：

１．You ought to have done the experiment more carefully.

２．Mary ought not to have left home without telling her mother.

［训练］

1.   Yesterday, Jane walked away from the discussion. Otherwise, she ___some thing she would regret later. (上海９６年高考题)

Ａ。　Had said   B. Said    C. Might say   D. might have said

2.   ----We quarrelled with the waiter about the bill.

-------How silly! You ____ to the manager. (NMET94)

A. must talk   B. Should have talked   C. Could talk    D. would

3.   Tom ought not to _____me your secret, but he meant no harm.

A. have told   B. Telll   C. Be telling   D. having told

4.   There was plenty of time. She ____.

A. mustn’t have hurried    B. Needn’t have hurried 

C. must not hurry         D. couldn’t have hurried

5.   The magazine I borrowed form my friend is not on my desk. My little brother ____.

A. may have taken away it      B. Must have taken it away

C. must take it away           D. should have taken it away