虛擬語氣在主語從句中的應用
這一類型主要包括It is (was) important (necessary, desirable, imperative, advisable)that. . .句型。如：
It is impossible that he should go home. 他不可能會回家去。
It is necessary that I should return it right now. 我有必要馬上把它還回去。
It is important that we should speah politely. 我們說話要有禮貌，這是很重要的。
It is not necessary that everyone be a scientist. 沒有必要使每一個人都成爲科學家。
It is imperative that we should practise critidsm and self-criticism. 應當進行批評與自我批評。
二、It's a pity…類
It is a pity that she should fare so badly. 她竟吃得這麼差，真可憐。
It's a pity that he should be so obstinate. 真遺憾他竟這樣倔犟。
It was a pity that you couldn't come. 你不能來，真是太遺憾了。
It is a pity that she failed the driving examination. 她沒通過駕駛考試真是遺憾。
It is his desire that a medical man should stay here. 他希望有一個醫務人員留在這裏。
三、It's desired…類
這種主語從句還常用在It is (was) desired (suggested, settled, proposed, requested, decided, etc. ) that...句型。如：
It is requested that a vote be taken. 建議付諸表決。
It is settled that you leave us, then? 那麼你肯定要離開我們羅?
It was proposed that this matter be considered at the next meeting. 有人提議這事下次會議再討論。
It is desired that this rule should be brought to the attention of the staff. 希望這條規則引起全體職員的注意。
注意：
(1) 在現代英語中，有時也可不用虛擬語氣而用陳述語氣，但初學者宜慎用。
(2) 在It is amazing (strange, surprising, astonishing, a pity, a shame)以及 I am surprised (sorry) 和I regret等結構後的that 從句中有時也用should，表示說話人的驚異、懊悔、失望等情感，常含有“竟然”之意：
It's strange that he should be so rude. 他竟如此無禮，真是奇怪。
I'm surprised that he should have failed. 他竟然失敗了，這使我很吃驚。
若不用虛擬語氣也可以，則不帶感情 色彩，比較：
It's a pity that he failed the exam. 他考試沒及格，真是遺憾。
It's a pity that he should have failed the exam. 他考試竟沒及格，真是遺憾。
