5.用在if only感叹句中

  当表示“但愿”，“要是…就好”时，它的用法和wish基本相同，只是更富有感情色彩，表示一时很难实现的愿望。例如：

  1)If only I knew what you wanted.

  2)If only you hadn’t told him what I said, everything would have been all right.

  6.用在以as if (as though) 引出的方式状语从句中

  当表示过去想象中的动作或情况时，用过去完成时;当表示和现在事实相反或对现在情况有所怀疑时，用一般过去时。例如：

  1)The old couple loved the orphan girl as if she had been their daughter.

  2)It seems as if it were spring.

  7.用在某些虚拟的定语从句中

  例1：He was the very person I should have been wished to see.

  例2：It’s (high) time that we went to class.

  8.用以表示说话人的主观愿望或选择，仅用在一些惯用句型的从句中

  例1：I’d rather they came tomorrow.

  例2：He’d rather I went to Fuzhou by sea.

  例3：I’d just as soon you didn’t watch television this evening.

  但had rather, would rather, would just as soon, would sooner等惯用语如用在简单句中，其后都用不加to的动词不定式。例如：

  1)I’d rather die than give up my principle.

  2)I’d just as soon (would sooner) resign than take part in such dishonest deals.

  二、用固定的情态动词表示的虚拟语气

  1. should +动词原形(有时省略should)

  (1)用在动词如advise, command, demand, desire, insist, order, propose, recommend, request, require, suggest, urge等后的宾语从句中。例如：

  1)They requested that we (should) send a delegation to their country.

  2)She urged that he write and accept the post.

  (2)用在it is suggested, it is desired, it is required, it was ordered, it was proposed, it has been decided, it is necessary (essential, imperative, important, desirable) that等引出的主语从句中。例如：

  1)It is desired that we (should) get everything ready by tonight.

  2)It is necessary that the teacher (should) have a thorough knowledge of the subject he teaches.

  (3)用在suggestion, motion, proposal, order, recommendation, plan, idea, requirement等引起的表语从句和同位语从句

  例如：He put his coat over the child lest he should catch cold.

  2.用在表示比拟的方式状语从句中

  例如：They talked as if they had been friends for years.

  3.用在表示虚拟情况的定语从句中

  例如：It is high time you handed in your test paper.

  4.用在某些表示主观愿望的名词从句中

  例1：I wish I were as strong as you.

  例2：He insisted that we (should) take up the matter at the meeting.

  5.用在婉转的请求、建议、批评等句子中

  例1：Could you spare me a few minutes?

  例2：You might have told me earlier.

  例3：Hadn’t you better go and see you dentist about that tooth?

  6.用在表示祝愿的简单句中

  例1：Long live world peace.

  例2：May you succeed.