英语虚拟从句用法

英语虚拟从句用法

虚拟语气在宾语从句中的用法
在动词suggest,order,demand,propose,request,command,insist等后的宾语从句中,用虚拟语气（即Should+动词原形或只用动词原形）来表示愿望、建议、命令、请求等.在动词wish /would rather后的宾语从句中,用过去式表示与现在事实不符,用过去完成式表示与过去事实不符.如：
I suggest that we（should）set off at once．
The doctor insisted that the patient (should)be X-rayed．
I wish I were as strong as you．
I would rather that you hadn”t told him．
　　　　　　　
虚拟语气在主语从句中的用法
　在It is necessary/important/strange/natural；It is requested/suggested/desired/proposed；it is a pity等结构后的主语从句中要用虚拟语气,即Should+动词原形或只用动词原形.如：
　It is necessary that he（should）be sent there at once．
It is requested that Professor Li（should）give us a speech．
　It is desired that we（should）get everything ready by tonight．
虚拟语气在表语从句、同位语从句中的用法.
　在 suggestion, proposal,idea,plan,order,advice等名词后的表语从句、同位语从句中要用虚拟语气,即should+动词原形或只用动词原形.如：
　Our suggestion is that you（ should）be the first to go．
　My advice is that we（should）send for Doctor Li．
　Do you know the order that you（should）keep watch?
虚拟语气在其他状语从句中的用法
　在as if引导的状语从句中,用过去式表示与现在事实不符,用过去完成式表示与过去事实不符；在so that,in order that引导的状语从句中,常用should/would/could/might+动词原形来表示虚拟语气.如：
　They talked as if they had been friends for years．
　She stayed at home for a few days so that she could take care of her mother．
　He took a taxi to the station so that she should not miss the train．
虚拟语气在定语从句中的用法：
　在it is time后面的定语从句中常用过去式表示虚拟.