高三复习之情态动词&虚拟语气.ppt

高三复习高三复习 之之 情态动词情态动词 & 虚拟语气虚拟语气一.情态动词的用法 1.表推测：现在过去肯定must+ V原型must+ have done否定cant+ V原型cant / couldnt + have done可能性may+ V原型may / might +have done2.表虚拟 should / shouldnt have done need / neednt have done could have done ought to have done 二.虚拟语气1.if 引导的虚拟条件句 情况从句主句与现在事实相反过去时（be动词用were）would/could/should/might +动词原型与过去事实相反过去完成时（had done）would/could/should/might +have done与将来事实相反过去时；should/were to+动词原型would/could/should/might +动词原型注意：省略if 的情况：当虚拟条件句中有should; had; were时，可以省略if，而把should；had；were 提到主语前，变为倒装句 含蓄条件句：with；without；but for等表达条件 错综条件句：主从句时间不一致2.表建议，命令，要求等的单词后接名词性从句 suggest；order；insist；suggestion；等 should+动词原型3.wish/if only /as if的虚拟语气 与现在的事实相反用过去时 与过去的事实相反用过去完成时 与将来的事实相反用would、could+动词原型4.would rather 的虚拟语气： 与现在和将来的事实相反用过去时 与过去的事实相反用过去完成时5.It is +adj /n+that 从句 （strange/ important/natural / a surprise等）： should+动词原形/should have done6.Its (high/about) time that .: 用过去时或should+动词原形