2018-05-12 大学英语语法结构梳理 虚拟语气

虚拟语气

（一）虚拟语气知识点讲解

虚拟语气与情态动词

1. if引导的虚拟语气

假设类型 if 从句谓语v 主句谓语v

与现在事实相反 动词用过去式（be用were） would

should

could

might

与过去事实相反 Had+done would

should

could

might

与将来事实相反 were to    +do

should      +do would

should

could

might

（1） 省略if的虚拟倒装

had + 主语（not）done

should + 主语 + do

were +主语+ to do

（2）含蓄虚拟

without = but for 

with

（3）错综（混合）虚拟

2. 其他形式虚拟

(1）wish / wished

主

（2）as if / as though

主

3）if only

主

（4）would rather = ’d rather

主

would rather do / not do

(5)用表示建议、命令、要求等词引导的名词性从句中

that + 主语

两步解题方法：

①圈出标志词（表建议、命令、要求的词）

② 选出动词原形

suggest/-ed/-ion    propose/-d/-sal  order/-ed

ask/-ed    require/-d/-ment  request/-ed 

desire/-d/-rable  demand/-ed  command/-ed

insist/-ed/-ent/-ence          recommend/-ed/-ation

move/motion    urge/-ent    direct/-ed

advise/-ce/-able    important    vital 

essential      necessary      imperative

（6）It's/was + time

      high time      + that +主+ did

    about time

（7）lest (that)

for fear that    + 主语 + should + do

(in case)

in case

（8）跳层虚拟

真实，otherwise / or + 虚拟

虚拟，but + 真实

真实—过去时 / must have done

虚拟—would / could + have done

3. 情态动词+ have done

must + have done

can / could + have done

may / might + have done

should / ought to + have done

shouldn't / oughtn't to + have done

needn't + have done

must

表命令    “必须”

表推测    “一定”

need 

情态动词    “必要” + do

  实义动词    “需要” + to do

need doing = need to be done