虛擬語氣在託福考試的考點中不是那麼的重要，但是鑑於它的活躍表現，我們對它還是要有一定的了解的，這對於解讀也是很有幫助的。
雅託邦小編今天就給大家說說虛擬語氣，虛擬語氣是英文中一種特殊的語言現象，其主要是用來表達與事實相反的一個陳述，所表達的一個強烈的願望、遺憾、感慨、後悔、責備等等的一些語義。
虛擬語氣大致可以分為三類：
一、對現在事實的虛擬
其基本的形式為：If+were/did等的過去式...，..would/could/should/might+do。比如像：If I were a bird, I would fly to the moon.
(真實情況是： I 'm not a bird, so I will not fly to the moon.)
二、對過去事實的虛擬
其基本的形式為：If+had done...，..would/could/should/might+have done。比如像：If she had been warned earlier, she wouldn't have broken the rules.
(真實情況是：She was not warned earlier and She broke the rules.)
小編貼士：這種的虛擬是可以進行倒裝的。比如像：Had the letter been sent out, it would have our friendship train.其等於：
If the letter had been sent out, it would have thought our friendship.
三、對將來事實的虛擬
其基本的形式為：If+should do...，..would/could/should/might+do，這個意思就有點像我們常說的「萬一」。比如像：If he should forget the date, I might teach him a good lesson.（真實情況是：He is unlikely to forget the date.）
小編貼士：這種虛擬也是可以進行倒裝的。Should my car fail, I would have to return home on foot.
其等於：If my car should fail, I would have to return to home on foot.
在這裡大家有一些注意事項要記得：
一、部分動詞的賓語從句中需要用虛擬語氣，形式是should do，但是其中常常會省略掉should。這一類的動詞有insist, demand, suggest, withdraw, order, require, decide, ask, request等等。使用的時候像這樣：The professor suggested that the students (should) collect enough materials before they work on this project.不過，如果上面提到的動詞是以名詞形式出現的時候，後面的that從句仍然是要用虛擬語氣的。比如像：He gives me the suggestion that I (should) eat breakfast every moning.
二、在一些慣用語的後面也是經常需要用到虛擬的，以此來表示與事實相反或者難以實現的事情。這一類的習語有：as if, as though, but for, otherwise, without, wish, if only等等。使用的話像：But for your help, I would not have arrived here in time.,
三、在一些形容詞引導的that從句裡面必須要用虛擬語氣（should）do，但是由於should經常是被省略的，所以實際上用的就是動詞原形,像這一類的形容詞有：It is important/necessary/proper/imperative/essential/advisable等+that。這種句子有：It is necessary that he (should) realize his situation.
照例，為了讓那個各位有個更加清晰的認識，我們來進行例題解析：
例：Abraham Lincoln insisted that --- not just on mere opinion but on moral purpose.
(A) to the base centre
(B) for democracy to be based
(C) the centre be -based
(D) clean democracy is based
解析：在題目裡面，動詞insist的後面的賓語從句需要用虛擬語氣，從句謂語應該是should do或者（should）do，而在選項裡面，只有C符合要求，謂語是動詞原型，所以選C。
以上就是雅託邦小編給大家分享的關於虛擬語氣的解析，望大家參考有所收穫，有什麼問題歡迎來和小編討論哦！