can能力,may请求,must命令,should建议,can"t猜测,mustn"t禁止.请各造一个句子need 和shouldn"t表示什么?也请各造一个句子

Question

can能力,may请求,must命令,should建议,can't猜测,mustn't禁止.请各造一个句子
need 和shouldn't表示什么?也请各造一个句子

Answer 1

首先, 必须澄清一下的是, 这些情态动词的用法是互相交叉的
因此, 你的分类并不全面
[常用的分类, 不包括全部情态动词]
1.能力
can/could (有时需使用be able to, manage to)
The baby can't(couldn't) dress himself.
2.许可
can/(could)/may/(might)
Can/May I watch TV tonight?
Yes, you can/may.
3.命令与禁令
must (not), will(军令式的粗暴命令), [shouldn't]
You mustn't play now!
You will finish the job tomorrow!
[据 Practical English Usage, 表示一种强制的,粗暴的命令, 就像预言未来必定发生的事件一般]
4.必要性
must, need, should, ought to, need (not)
Must/Need I come here tomorrow?
No, you needn't.
You should/ought to come here on time.
5.推测
can (not), could (not), must, might (not), may (not)
It can't be!
It must be Tom.
He may be in the office.
6.建议
[should 更常见于 虚拟语气中] had better
I suggest that you should bring some pork tomorrow.
He had better do something for his family, hadn't he?
(注意Tag Question疑问尾句的变化)
另外,情态动词必须带 [不加to的动词不定式] 也就是原形,因此 need to do/need doing的用法不属于情态动词(显然,need这时候有人称变化)
要知道详细的用法, 请查阅一本好的语法书
(A Practical English Grammar, 薄冰, .)