- A+
1）表才能时意味着凭膂力或脑力或技能等可以无甚阻力地去做某事。
I can climb this pole. 我能爬这根杆子。
He is only four, but he can read. 他只需4岁，但已认得字了。
2）标明估测口气的用法时，can只能用于疑问句和否定句，用于否定句的时分必需要有充分的理由阐明。如：
Can he be at home? No, he can't be at home, because I met him in the street just 5 minutes ago.
他可以在家吗？不，他不可以能在家，因为我5分钟之前才在街上遇到他。
2、may (might)
1）标明恳求、可以、答应。
You may drive the tractor. 你可以开那台迁延机。
2）表主张（可和as well 连用）
You may (might) as well stay where you are.
你仍是原地待着好。（may as well 有“仍是……的好”的意义）
3）表可以（实际上）。可以指曩昔时刻，也可以指如今时刻，但口气愈加不必定，只能用于必定句和否定句。
He 
may be at home. 他可以在家。
She may not know about it. 她可以不晓得这件事。
He was afraid they might not agree with him. 他忧虑他们可以不附和他的定见。
They might be having a meeting, but I'm not sure. 他们有可以在开会，不过我不必定。
3、must
1）标明有必要、必要
We must do everything step by step. 咱们有必要故步自封地做悉数作业。
2）must 的否定式有两个：当答复由must致使的疑问时，否定答复要用needn't或don't have to标明“不必”、“无须”、“用不着”
3）标明估测口气的用法，意为“准是、必定”等，只用于必定句，而且要有足够的理由阐明。
He must have passed the exam, because he looked so happy.
他必定经过考试了，因为他看起来如此的开心。
4. have to
have to的意义与must是很接近的，只是have to 比照偏重客观需要，must偏重阐明片面观点。
I must clean the room.（片面主意）I have to clean the room.（客观需要）
另外，have to 能用于更多时态：
We had to be there at ten. 咱们得在十点钟到那里。
We will have to reconsider the whole thing. 这悉数咱们将不得不从头加以思考。
have to 的否定式：don't have to do 标明“不必做……”之意。
5、would
1）表自愿。
They would not let him in because he was poorly dressed. 他们不让他进入因为他穿戴破旧。
I said I would do anything for you. 我说过我情愿为你做任何事。
2）表曩昔重复发生的动作或曩昔的一种倾向。
Every time she was in trouble, she would go to him for help.
她每遇到费事都会向她求助。他告诉我盒子打不开了。
6、ought to
表责任，意为“大约”（因责任、责任等该做），口气比should稍重。
You are his father. You ought to take care of him. 你是他父亲，应当管他。
You oughtn't to smoke so much. 你不大约抽这么多烟。
7、used to
标明曩昔的习气动作或状况，如今不复发生或存在。疑问式和否定式有两种。
He used to live in the countryside, but now he lives in the city.他曩昔住在乡下，如今住在城里。
There used to be a building at the street corner, but it has been pulled down.
大街角落处曩昔有座高楼，如今拆了。
I usedn't (didn't use) to smoke. 我曩昔不抽烟。
Used you (Did you use) to go to school on foot? 你曩昔常步行去学校吗？
难点释疑：
（一）need和dare的用法比照
need和dare既可用作神态动词，也可用作实义动词。用作神态动词时，首要用于否定句和疑问句。用作实义动词时，可用于各种句式。
1.用作神态动词
You needn't telephone him now. 你如今不必打电话给他。
I don't think you need worry. 我想你不必忧愁。
She dare not go out alone at night. 她晚上不敢一自个出去。
Not one of them dared mention this. 他们谁也不敢提这件事。
2.用作实义动词
You don't need to do it yourself. 你不必亲自做这件事。
We need to tell them the news. 咱们需要把这消息告诉他们。
The table needs painting (to be painted). 桌子需要油漆一下。
We should dare to give our own opinion. 咱们要勇于提出自个的观念。
He did not dare (to) look up. 他不敢举头看。
（二）神态动词后跟结束式和进行时的用法
1.神态动词后跟结束式，表“应当现已……”，“想必现已……”，“正本可以……”等意。
I should have finished the work earlier. 我应当早一点结束这项作业的。
He isn't here. He must have missed the train. 他还未到，必定是没赶上火车。
Where can (could) he have gone? 他能到那里去了呢？
You may (might) have read about it. 你可以在报上现已读到这件事了。
You could (might) have been more careful. 你正本可以更细心的。
He needn't have worried about it. 他本不必为此事忧虑。
There was a lot of fun at yesterday‘s party. You ought to have come, but why didn't you?
昨日的集会非常有意思。你本大约来，为何不来呢？
2. 神态动词后跟进行时，标明“想必正在……”，“可以正在……”，“应当正在”等意。
It‘s twelve o’clock. They must be having lunch. 如今是十二点。他们必定正在吃饭。
They may be discussing this problem now. 他们可以正在论讨这个疑问。
