May can must guess Which tone is strong and which is weak There are also specific uses

May can must guess Which tone is strong and which is weak There are also specific uses

May (it's more likely than might)
Be able to do sth
He can understand her meaning
He must have finished his homework
You must do it/
Could is used in subjunctive mood or euphemistic mood (hoping to get a positive answer from others)
If I could go with you, I should feel very glad
Could I borrow you pan
Could is also the past tense of can

The difference between might, may, can and must

I just told the kids about this
（1）can
Can means physical or mental ability or objective possibility. It can also mean speculation about things. In spoken English, "can" is often used to replace "may" when asking or explaining whether a thing can be done. The past tense of modal verb "can" is "could", the negative tense is "cannot", which is usually abbreviated as "can't", and the negative tense of "could" is "could not", Can I help you / he can swim / that can't be Mr Li
（2）must
"Must" means "must" and "must", We must be very careful when we cross the road / it must be Jack / I haven't seen Kate today. She can't be here
Note: when using must, use must for positive answer and needn't for negative answer; when using must, use must for positive answer but can't for negative answer, No need. / must she be in the romm? – yes, she must. Or no, she can't
（3）may
May means permission, request or possibility. When you ask a question with may, the affirmative answer is usually yes or yes, you may. The negative answer is usually can't or must't. for example, may I ask you a question? - certainly
（4）might
"May" is the past tense of "may", which means the tone is more euphemistic when asking and weaker when guessing

In the table inference, the difference between must may could not and can not, could not, may not and might not

"Could" and "might" both have the meaning of guessing, and the tone is more euphemistic. But "could" is more positive than "might"