动词根据功能分为四类：
1). 实意动词（Notional Verb）.
2). 系动词（Link Verb）. am, is, are,
3). 助动词（Auxiliary Verb）. be ,have/has, do/does, shell, ...
4). 情态动词（Model Verb）. 通常和实意动词一起使用。
a. 动词有数量和时态的变化，时态通常有三类：现在，将来，过去。
b. 根据动作进行的状态可分为：一般，进行，完成。
c. 使用动词时通常将（1）和（2）结合，例如：一般现在时，过去进行时...
1. He goes to school every day.
2. He went to hospital last night.
动词形态变化总结：
| 动词原形 | 单三 | 现在分词 | 过去式 |
|---|---|---|---|
| play | plays | playing | played |
| have | has | having | had |
| go | goes | going | went |
1. 实意动词
(1). 实意动词的特征（动作有实际意义的动词。动词有时态上的变化）；
come, read, go, watch, play, fly
1. He comes from Shenyang; (单三，一般现在时)
2. She is reading story books. (现在进行时)
3. They went to America yesterday. (went--go的过去时)
4. We have watched the game for three times. (现在完成时)
5. My mother will fly back to China next month. (将来时)
实意动词的否定，提问，回答
(2). 使用助动词进行否定，在助动词 do, does, did 后面加 not;
[do,does=用于一般现在时。did用于一般过去时。 do not = don`t， does not = doesn`t，did not = didn`t]
1. I don`t go to school by bus.
2. She doesn`t watch TV everyday.
3. They didn`t swing last night.
(3). 使用助动词进行提问和回答
1. He often plays golf.
疑问：Does he often play(用原型) golf? -- Yes, he does. / No, he doesn`t.
2. They go to school by bus.
疑问：Do they go to school by bus? -- Yes, they do / No, they don`t.
3. Sam had breakfast yesterday.
疑问：Did Sam have(用原型) breakfast yesterday? -- Yes, he did / No, he didn`t.
2. 情态动词：can/ could/ may/ might
(1). can/ could 表示能力，用 be able to 代替 can/ could , 现在/ 过去 的能力客观可能性（can的可能性大），表示请求，允许。
1. He can /could / is able to swim.
2. He can/ could come tomorrow.
3. Can/ Could I stay here?
(2). may/ might 表示可能性，may的可能性大 请求，允许，might更委婉。
口语中常用的回答：-- Yes,please. -- No, you can`t/ mustn`t.
1. He may/ might come here by bus.
2. -- May/ Might I join you? -- Yes, please. -- No, you can`t/ mustn`t.
练习：
1. She could speak French before, but now the can`t.
2. -- Might I come in ? -- Yes, please.
情态动词：should/ ought to / must (have to)
(3). must/ have to 表示必须，必要。must表现主观多一点，而have to 则表示客观多一点。
hava to 有时态和数量的变化。
must 和 have to二者的否定意义不大相同。
如：You mustn`t go 你不准去。 You don`t have to go. 你不必去。
1. You must get up early.
2. It`s going to rain, I have to go home now.
(4). should 表示劝告，建议，命令，其同义词是 ought to.
should 强调主观看法，而ought to 强调客观要求。在疑问句中通常用should代替 ought to.
1. You should/ ought to do the job right now.
2. Should they stay here now?
情态动词：need / don`t have to
(5). need 需要。可以作情态动词。也可作实意动词，有第三人称单数和时态的变化, 后面可加带to的不定式。
作情态动词。后面接动词原形。
1. He need come here early.
2. He needn`t come here early. [否定[
3. -- Need he come here early? -- Yes, he need. / No, he needn`t. [疑问]
作实意动词。有第三人称单数和时态的变化, 后面可加带to的不定式。
1. He needs to come here early. 单三
2. He doesn`t need to come here early. [否定]
3. -- Does he need to come here early. -- Yes, he does. / No, he doesn`t. [疑问]
(6). 回答must和 have to 的提问句时，否定式使用 needn`t, don`t have to 等回答方式。
1. -- Must I come here early tomorrow?
-- No, you needn`t. / don`t have to.
情态动词：had better / would rather
(7). had better 表示” 最好做某事“。had虽然是过去式，但不表示过去，better 后面接动词原形。
1. He had better eat more.
2. You`d better finish it right now.
(8). would rather 表示” 宁愿，宁可，最好，还是...为好“。语感上比” had better“ 要轻。
1. You would rather deal with it now.
否定形式分别为：
had better not + 动词原形
would rather not + 动词原形
1. He had better not eat more.
2. You would rather not deal with it now.
情态动词：used + v / would + v
(9). used to, would 表示过去习惯性动作，可翻译为”过去常常...“.
a. used to 可指过去的状态或情况，would则不能。
The novel used to be popuar. [这本小说过去很受欢迎].
b. would 表示反复发生的动作。如果某一动作没有反复性，就不能用would, 只能用used to.
1. He would practise English every week. [practise v 练习, 训练，经常性 [ˈpræktɪs]]
2. I used to live in Beijing.
c. used to 表示过去经常性或习惯性的动作或状态但现在已经结束，would则表示有可能再发生。
1. People used to believe that the earth was flat.
2. He would go to the park as soon as he was free. [as soon as 立刻; 一…就…]
情态动词的否定和疑问
(10). 情态动词的否定：情态动词 + not + v原形
1. He can`t sing an English song.
2. He may not know her.
3. He mustn`t go there.
4. He doesn`t have to go there.
(11). 情态动词进行提问：情态动词 + 主语 + v原形
1. -- Can he sing an English song? -- Yes, he can. / No, he can`t.
2. -- Must he go there? -- Yes, he must. / No, he needn`t.
3. -- Does he have to go there? -- Yes, he does. / No, he doesn`t.
练习：
1. -- Can / Could I stay here? -- Yes, please.
2. -- Must she go back now? -- No, She needn`t.
3. -- Does he have to get up at 9:00? -- Yes, he does.
(12). 情态动词 + have + p.p [情态动词 + 现在完成时]
a. 表达过去事实。
b. 推测的含义（但助动词should例外）,表示”可能已经...“.
1. He can / could have arrived. [他可能已经到了 （可能性最小）]
2. He may / might have arrived. [他可能已经到了 （可能性小）]
3. He must have arrived. [他准是已经到了 （可能性大）]
should + have + p.p：本应该...
needn`t have + p.p：本不需要...
1. He should have arrived. [他本应该到了（但没到）]
2. They should have finished the work. [他本应该已经完成工作（但没完成）]
3. You needn`t have done so. [你本不需要那么做]
must + have + p.p：准是已经...(肯定)
can`t + have + p.p：不可能已经...
1. He must have arrived.
2. He can`t have arrived.
该笔记整理于崔荣容老师的视频讲解：https://www.bilibili.com/video/av2639206