常见题型：选择题、语法填空、完形填空
情态动词(modal verbs)本身有一定词义，但不能独立作谓语，需与动词原形连用，表示说话人的态度、情感和看法，如能力、允许、义务、推测、虚拟等。情态动词没有人称和数的变化，后接动词原形。
一、情态动词 + have done 7种用法(核心考点！)：
① must have done — 一定做过(过去肯定推测)
The ground is wet. It must have rained last night. 地面湿了，昨晚一定下过雨。
⚠️ 否定推测不用mustn't，用can't/couldn't！
② can't/couldn't have done — 不可能做过(过去否定推测)
He can't have gone to Beijing. I saw him just now. 他不可能去了北京，我刚才还看见他了。
③ may/might have done — 也许做过(过去可能推测，might语气更弱)
She may have missed the bus. 她可能没赶上公交车。
He might have forgotten the appointment. 他也许忘了约会。
④ could have done — 本可以做(但没做)
You could have passed the exam if you had studied harder. 你本可以通过考试的(但你没通过)。
⑤ should/ought to have done — 本应该做(但没做，含责备)
You should have informed me earlier. 你本应该早点通知我的。
⚠️ shouldn't have done — 本不该做(但做了)
⑥ needn't have done — 本不必做(但做了)
You needn't have brought so many gifts. 你本不必带这么多礼物的。
⚠️ 区分: didn't need to do — 不必做(也没做)
I didn't need to go to the station, so I stayed home. 我不必去车站，所以待在家了。
⑦ would have done — 本会做(虚拟语气主句)
If I had known, I would have helped you. 如果我当时知道，我会帮你的。
二、情态动词推测(现在/进行)：
must be — 一定是(肯定推测) → He must be at home now. 他现在一定在家。
may/might be — 可能是(可能推测) → He may be in the library. 他可能在图书馆。
can't be — 不可能是(否定推测) → He can't be serious. 他不可能是认真的。
must be doing — 一定正在(进行推测) → He must be sleeping now. 他现在一定在睡觉。
三、情态动词基本用法：
can/could: 能力(I can swim.)/许可(Can I go now?)
may/might: 许可(May I come in?)/可能(It may rain.)
must: 必须(You must finish.)/推测(一定是)
should: 应该(You should study hard.)/竟然(It's strange that he should be late.)
need: 需要(Need I go? 作情态动词) / 实义动词(I need to go.)
dare: 敢(Dare he say so?)
选择题1-2题 + 语法填空0-1题, 约占语法总分10%