情態(tài)助動(dòng)詞用法簡(jiǎn)述
dare, need
① dare作情態(tài)動(dòng)詞用時(shí), 常用于疑問(wèn)句、否定句和條件從句中, 過(guò)去式形式為dared。
eg. How dare you say such horrible words to me?
② need 作情態(tài)動(dòng)詞用時(shí), 常用于疑問(wèn)句、否定句，相當(dāng)于肯定句中一般用must, have to, ought to, should。
eg. Need I finish the work today?
Yes, you must. / No, you needn't.
③ dare和 need作實(shí)義動(dòng)詞用時(shí)， 有人稱、時(shí)態(tài)和數(shù)的變化，在肯定句中，dare后面常接帶to的不定式，在疑問(wèn)句和否定句中，dare后面可接帶to或不帶to的不定式，而need后面只能接帶to的不定式。
eg. She doesn't dare (to)answer.
She needs to cook dinner for her sisters.
五. shall, should
① shall 用于第一人稱，征求對(duì)方的意見(jiàn)。
eg. What shall I do ?
② shall 用于第二、三人稱，表示說(shuō)話人給對(duì)方的命令、警告、允諾或威脅。
eg. You shall be punished,you bad boy!
六. will, would
① 表示請(qǐng)求、建議等，使用would使語(yǔ)氣更加緩和。
eg. Would you give me a cup of coffee, please?
② 表示意志、愿望和決心。
eg. I will never do that again.
③ would表示過(guò)去反復(fù)發(fā)生的動(dòng)作或某種傾向。
eg. During that summer, he would visit me every other day.
④ 表示估計(jì)和猜想。
eg. It would be about may when she come back to China.
七. should, ought to
① should表示“應(yīng)該”，ought to表示義務(wù)或責(zé)任，語(yǔ)氣更嚴(yán)重。
eg. I should help her because she is in trouble.
You ought to take care of her because she is your daughter.
② 表示勸告、建議和命令，should, ought to可通用，但在疑問(wèn)句中常用should。
eg.Should I open the window?
③ 表示推測(cè)， should , ought to (客觀推測(cè)), must(主觀推測(cè))。
eg. She must pass the exam. (斷定)
She ought to/should pass the exam.(不太肯定)