2017年12月英語四級語法:非真實條件句

　　我們都知道，在大學英語四級考試中，單獨考察英語四級語法的題型很少，但是英語四級語法知識點卻貫穿整張試卷，下面是新東方網英語四級頻道為大家整理的大學英語四級語法知識，希望可以為大家帶來幫助。

　　2017年12月大學英語四級語法大全目錄

　　16.2 非真實條件句

　　時態：可以表示過去，現在和將來的情況。它的基本特點是時態退後。

　　a.　 同現在事實相反的假設。

　　句型 ： 條件從句　　　　　主句

　　一般過去時　　　should( would) +動詞原形

　　If they were here, they would help you.

　　b.　 表示於過去事實相反的假設。

　　句型： 條件從句　　　　　 主句

　　過去完成時　　　 should(would) have+ 過去分詞

　　If she had worked harder, she would have succeeded.

　　The rice would not have been burnt if you had been more careful.

　　If my lawyer had been here last Saturday, he would have prevented me from going.

　　If he had come yesterday, I should / would have told him about it.

　　含義：He did not come yesterday, so I did not tell him about it.

　　If he had not been ill and missed many classes, he would have made greater progress.

　　含義： He was ill and missed many lessons, so he did not make greater progress.

　　c.　 表示對將來的假想

　　句型：　 條件從句　　　　　　 主句

　　一般過去時　　　　　 should+ 動詞原形

　　were+ 不定式　　　　 would + 動詞原形

　　should+ 動詞原形

　　If you succeeded, everything would be all right.

　　If you should succeed, everything would be all right.

　　If you were to succeed, everything would be all right.

　　2017年12月大學英語四級語法大全目錄