虚拟语气的用法

1，   条件句中的谓语动词形式 主句谓语动词形式 现在 动词过去式（be 用were） Should/would/could/might +动词原形 过去 Had done Should/could/would/might have done 将来 动词过去式，should+动词原形或者 were to be Should/would/could/might +动词原形 2,省略if 省略if ，则把were，had ,should 提到主语之前，引起倒装。Eg:Had it not been for the fact that she broke her leg ,she might have passed the exam . 3,错综时间虚拟条件句 有时主句和葱姜动作发生时间不同，动词形式根据表示的时间来调整 Eg : would you be surprised if i had arrived yesterday without letting you know beforehand? 4,含蓄虚拟条件句  条件句中的虚拟语气除了用if 以外，还可以用but for ,without, with ,in the absence of , under ,but,or ,but that ,otherwise, supposing ,provided 等 Eg :But for their help , we could not have finished the work on time . 5, wish 引导的虚拟语气，用法与表格一致 6， would rather ，would sooner ，would just as soon , might as well ,would prefer 后面跟虚拟语气，表宁愿，但愿。形式为would rather +主语+过去式表示现在或将来的愿望。Wouldrather+have done 表示过去的愿望 7，表示命令，建议或要求的动词后用（should ）+动词原形，ask ,advise,move,prefer ,propose , order,recommend , intend , insist , determine , decide , commend，它们的变形也用虚拟语气 8,it is +引起虚拟的形容词或过去分词 that +(should) do ，这类词有 appropriate ，advisable，desirable，important ，imperative ，necessary ，vital urgent，essential等 9，it is high/about time that+动词过去式