虛擬語氣是英語中一種重要的語氣形式，也是英語語法中一個重要的語法點。
　　由于虛擬語氣所涉及的內容比較廣，一些語法書對其的闡述也很繁雜，所以同學們在學習過程中很難掌握其用法，在使用過程中或考試時也很容易出錯。為了便于大家理解和記憶，筆者對虛擬語氣作了一個“新”歸納，供大家參考。
　　虛擬語氣的使用主要體現在三個方面：虛擬條件句、虛擬語氣在某些從句中的運用，以及虛擬語氣的一些特殊用法。
　　虛擬條件句
　　虛擬條件句就是對現實條件的一種虛擬假設，所假設的條件一般不符合事實或與事實相反或在現實中發生的可能性極小。根據時間的不同，虛擬條件句可分為三種，即與現在事實相反的虛擬條件句、與過去事實相反的虛擬條件句及與將來事實相反的虛擬條件句。具體情況請看下表：
　　
　　例句：
　　1.表示與現在事實相反
　　If I had enough money now ， I would lend it to you.
　　If I were you ， I would go to tell him the real feeling upon him.
　　2.表示與過去事實相反
　　If he had taken your advice ， he wouldn‘t have made such a bad mistake.
　　She would have come to enjoy the party if she hadn‘t been very busy.
　　3.表示與將來事實相反
　　I would go shopping with you if it were to be Sunday tomorrow.
　　If he were to be given another chance to do it again， he could certainly achieve more.
　　1.虛擬條件句的倒裝
　　在虛擬條件句中，為了強調所假設條件的虛擬性，或突出說話人的一種主觀愿望，虛擬條件句可用倒裝結構。虛擬條件句的倒裝是通過去掉if，把條件從句謂語中的助動詞、情態動詞或系動詞放在句首實現的。例如：
　　Had I been（= If I had been ） in that situation， I would not have let the thief escape away with so much money.
　　Should there be （= If there should be） a drought， what should we do at that time ？
　　2.錯綜時間條件句
　　有時條件從句的動作和主句的動作發生的時間并不一致，這時謂語動詞的形式應根據它所要表示的具體時間來決定。例如：
　　If we hadn‘t been working hard in the past few years ， things wouldn’t be going so smoothly.
　　If the Party hadn ‘t led the Chinese people to liberate the country，Chinese people would still live a life in pain and poverty.
　　3.含蓄條件句
　　有時假設的情況并不以條件從句的形式表現出來，而是通過某個介詞或介詞短語（如：with， otherwise， without， but for， in that position ）、上下文或其它方式表現出來。這種句子稱為含蓄條件句。例如：
　　But for the help from you ， I would not have had the chance to go to college.
　　I would never mind you making such loud noises， but， you see， my baby is in a deep sleep.
　　It was so quiet ； you could have heard a pin drop.