虛擬語氣基礎知識梳理

王新民

虛擬語氣是高中英語語法的難點之一。在近年來的高考試題中，虛擬語氣不斷出現(xiàn)。因此，掌握好虛擬語氣，對于我們正確地理解英語會有很大的幫助，從而直接或間接地提高我們的高考分數(shù)。

一、虛擬語氣在含有非真實條件狀語從句的主從復合句中的應用

如果條件狀語從句敘述的情況與已經(jīng)發(fā)生情況相反，或者在未來發(fā)生的可能性極小，甚至根本不可能發(fā)生，這種條件狀語從句稱為非真實條件句。虛擬語氣在含有非真實條件狀語從句的主從復合句中的應用有以下幾種情況：

（一）與過去事實相反的假設

其基本句型是：

“If+主語+had done， 主語+should/would/could/might have done”。如：

If I had taken the teacher's advice，I would have gone to college.

（二）與目前事實相反的假設

其基本句型是：

“If+主語+did（be動詞常用were），主語+should/could/would/might do”.如：

If I were you，I would follow the teacher's advice.

（三）對未來幾乎不可能發(fā)生的情況的假設

對于未來的情況，如果發(fā)生和不發(fā)生的可能性同時存在，我們還是要用真實條件句。只有當發(fā)生的可能性極小或者根本不可能發(fā)生的時候才用非真實條件句。其基本句型是：

“If+主語+should do/were to do//did，主語+should/could/would//might do”.如：

If it were to rain tomorrow，I would give you 100，000，000 US dollars.

[注意]

（一）有時，某些介詞短語、副詞或連詞的作用相當于非真實條件句。如：

Without his help，I couldn't have finished this task in such a short time.

He phoned to inform me of your birthday，oy I would have forgotten it.

（二）若從句的謂語中有助動詞had， should 或were，可把這些詞提到句首，而省略掉If。如：

Had I had enough money，I would have bought the house.

Should he come，tell him to ring me up.

Were I you，I would go with him.

（三）若條件句和主句的時間不一致，則要根據(jù)各自的時間使用相應的虛擬語氣的謂語動詞形式。如：

If I were you，I would have chosen the English department at that time.

If you had taken my advice just now，you would be better now.

二、虛擬語氣在其他狀語從句中的應用

（一）在so that或in order that引導的目的狀語從句中，常常使用虛擬語氣，其結構如下：

①當主句的謂語動詞是現(xiàn)在時或將來時時，從句的謂語動詞前要加may，can或will。如：

Please give me a little more time so that I can perfect it.

②當主語的謂語動詞是過去時時，從句的謂語動詞前要加could，should，might或would。如：

Our teacher spoke slowly so that we could hear clearly.

（二）當as if或as though引導的方式狀語從句所表達的內容與實際情況相反或者純粹是一種假設時，句子中通常使用虛擬語氣，其結構如下：

①從句用動詞的過去式表示從句的動作和主句的動作同時發(fā)生。如：

He speaks as if he were an Englishman.

②從句用“had+過去分詞”表示從句的動作發(fā)生在主句動作之前。如：

She was very heppy as if she had won the contest.

三、虛擬語氣在賓語從句中的應用

（一）wish后的賓語從句必須用虛擬語氣。其結構和as if或as though引導的方式狀語從句里的虛擬語氣相同。如：

I wish I were a bird and could fly freely in the sky.

I wish I had seen the film last night.

（二）suggest，order，demand，insist等動詞之后的賓語從句也常常使用虛擬語氣，其構成是“should+動詞原形”，其中的should可以省略。如：

Our teacher suggested that we read more books in our spare time.

[注意]

（一）susgest在表示“建議”時，其后的賓語從句可以用虛擬語氣；在表示“暗示；表明”時，要用陳述語氣。如：

The smile on his face suggested that he was satisfied with our work.

（二）insist在表示“堅持要”時，其后的賓語從句要用虛擬語氣；在表示“堅持說”時，要用陳述語氣。如：

The little boy insisted that he had never stolen the money.