八、情态动词和虚拟语气

情态动词

I.情态动词基本用法

情态动词 用 法 否定式 疑问式 简答式 can 能力（体力，智力，技能）

允许或许可（口语中常用）

可能性（表猜测，用于否定句或疑问句中） can not / cannot /can't do Can...do...? Yes,...can.

No,...can't. could couldn't do may 可以（问句中表示请求）

可能，或许（表推测）

祝愿（用于倒装句中） may not do May...do...?

　　　　　　　　 Yes,...may.

No,...mustn't/can't. might might not do Might...do...? Yes,...might

No,...might not. must 必须，应该（表主观要求）

肯定，想必（肯定句中表推测） must not/mustn't do Must...do...? to. Yes,...must.

No,...needn't/don't have have to 只好，不得不（客观的必须，有时态和人称的变化） don't have to do Do...have to do...? Yes,...do.

No,...don't. ought to 应当（表示义务责任，口语中多用should） ought not to/oughtn't to do Ought...to do...? Yes,...ought.

No,...oughtn't. shall 用于一三人称征求对方意见

用于二三人称表示许诺、命令、警告、威胁等 shall not/shan't do Shall...do...? Yes,...shall.

No,...shan't. should 应当，应该（表义务责任）

本该（含有责备意味） should not/shouldn't do Should...do...? will 意愿，决心

请求，建议，用在问句中would比较委婉 will not/won't do Will/Would...do...? Yes,...will.

No,...won't. would would not/wouldn't do dare 敢（常用于否定句和疑问句中） dare not/daren't do Dare...do...? Yes,...dare.

No,...daren't. need 需要,必须（常用于否定句和疑问句中） need not/needn't do Need...do...? Yes,...must. No,...needn't. used to 过去常常（现在已不再） used not/usedn't/usen't to do

didn't use to do Used...to do...?

Did...use to do...? Yes,...used.

No,...use(d)n't.

Yes,...did.

No,...didn't.