情态动词区别should/ought to have done用在否定句中和needn't have done 两者的区

情态动词区别
should/ought to have done用在否定句中和needn't have done 两者的区别,还有could have done,might have done,should/ought to have done三者的区别.我觉得他们各组的意思上都有差不多的,不过就是不知道应该怎么区分.

情态动词两要点;动词原形跟后面,说话语气较委婉,can表"能力"may"许可",must"责任"或"义务",否定回答"needn't"换;should"应该",would"愿",have to "被迫"表客观.
注释:对must构成的一般疑问句作否定回答只能用needn't.
can的用法
1.表能力
Can your sister skate / Can you sing / Can you dance
2.表示可能性
Can you go with us
We can go there by bus.
3.表示同意做某事,意为"允许","可以"
You can go now.
Can I have a look at your photos
4.表推测(主要用于否定句,疑问句)
It can't be Jay Zhou.
He can't be thinking about something.
must的用法
1.表示按命令,规定,责任等必须要做的事.
You must do all the homework by yourself.
You mustn't park your car here.
在回答由must引导的一般疑问句时,如果表示肯定,用must;如果表示否定,要用needn't.
-Must I come here tomorrow
-Yes,you must.
(No,you needn't.)
2.表示肯定的推测,意为"一定会","一定是",多用于肯定句.
It must belong to Karla.
He must be happy.
You must be joking.
must和have to 的区别是:must表示说话人的主观意愿,而have to 则表示客观要求,意为"不得不".
You must tell us what you have seen.
He had to walk home because the bus had left.
need的用法
need除了可用作行为动词外,还可用作情态动词,作为情态动词使用时,多用于疑问句和否定句,后面直接跟动词原形,作为行为动词时,后面跟带to的动词不定式.
他需要现在去看医生吗
Does he need to see a doctor now
Need he see a doctor now
need作为情态动词,意为"需要",无时态和人称的变化.
They needn't hand in their homework now.
Need I stay with you
(肯定回答为:Yes,you must.否定回答用No,you needn't.)
may的用法
1.表示"可以",用以询问或说明可否做某事.
May I use your pencil
You may come here tomorrow.
(在回答由may引导的问题时,常以Yes,please或certainly来表示允许或同意,而用please don't 或no,you mustn't来表示不允许和反对.)
2.用于表推测某事可能发生或某情况可能存在,意为"可能",一般不用于疑问句.
It may rain this afternoon.
She may still be in the classroom.注：①只做情态动词：must,can(could),may(might),
　　②可做情态动词又可做实义动词：need,dare
　　③可做情态动词又可做助动词：shall(should),will(would) ,ought to
　　④具有情态动词特征：have(had,has) to,used to
　　⑤情态动词表猜测