虚拟语气定义

虚拟语气是指说话人表示一种假设的情况，一种愿望，怀疑，推测，请求等，即认为动词所表示的动作或状态并非事实。

虚拟语气可用于状语从句，名词性从句，定语从句及其他结构中。虚拟语气的定义如果一件事不是真实的，而是虚拟的，就在这个动词身上加一个did。非真实条件句中的虚拟语气以下为If在非真实条件句中虚拟语气的形式和用法：假设类型 If从句 主句与现在事实相反 did(be用were) should / would /could / might+do与过去事实相反 had done should / would /could / might+have done与将来事实相反 1)did2)were to do3)should do should / would /could / might+doeg：

①If I were you ,I would reconsider their advice.如果我是你的话，我会重新考虑他们的意见。（与现在事实相反）②You would not have caught a cold if you had put on more clothes.如果你多穿了些衣服，你就不会得感冒了。（与过去事实相反）③If I were to / should do it ,I would do it in different way.如果我做这件事，我将用不同的方法做。（与将来事实相反）注意：在非正式文体中，如果If 条件句中有助动词were / should / had可将其提于主语之前（位于句首），再把If省掉，即形成部分倒装。当主从句所表示的时间不一致时，主从句按各自的时间采用相应的谓语形式。常见的有：

①If I were you ... = Were I you ... 如果我是你/我要是你......②If it were not for ... = Were it not for ... 如果要不是......③If it had not been for ...=Had it not been for ... 如果当时要不是......（③主句用：should / could / would / might + have done的形式，ps.在此结构中，had为助动词。若为谓语动词，则不能省略、倒装。）B.错综时间条件句主句和从句不是一个时间平台，需要分别在三个时间平台里“选形式”。从过完用had done，主过将用would do从用should / were to，主过将完用would have doneeg：

①If the weather had been more favorable ,the crops would be growing still better.如果天气更好的话，庄稼就会长得跟好些。（从句指过去，主句指现在）②If I were you ,I would have taken his advice.我要是你，我就采取了他的建议。（从句指现在，主句指过去）