Advice We'd better leave soon.
HAVE TO
Necessity, obligation I have to get to work by 9 every day.
You don't have to answer that question.
Do you have to wear a uniform at your school?
We had to start all over again.
I didn't have to wait long.
What did you have to do that for?
HAVE GOT TO
Necessity, obligation I've got to be home soon.
You haven't got to go already, have you?
Has he got to pay in advance?
MAY
Offers May I carry your suitcase, Madam?
Permission Children may use the pool with adult supervision.
May I start my presentation?
Possibility, uncertainty You should ask him. He may know Susan's telephone number.
I may have told you this before.
MAY NOT
Possibility, uncertainty You should introduce yourself; he may not remember you.
I had better call Anne. She may not have read my e-mail.
Prohibition Non-committee members may not vote on committee issues.
MIGHT
Criticism You might be more polite.
You might have told me you weren't coming!
Permission Might I ask you a question?
Possibility, uncertainty I might see you later.
I should call Anne. She might not have read my e-mail.
Suggestions You might consider taking up meditation.
I thought you might want to read this.
You might just as well order it on the internet.
MUST
Deduction That child is really talented. His parents must be proud of him.
That dress looks expensive. It must have cost a fortune.
Obligation I really must give up smoking.
You must keep this secret.
MUSTN'T
Prohibition You mustn't touch that Ming vase.
NEED
Necessity, obligation You needn't worry about that.
You need only just ask.
Need you make so much noise?
We needn't have bought any milk. We still have plenty at home.
NEED TO
Necessity, obligation Do you have a minute? I need to talk to you about something.
I don't need to be told that I should lose weight.
Do you need to use the hairdryer?
If you want good results, you will need to work harder.
I needed to have my hair cut.
Why did they need to change the lock?
We didn't need to buy any milk. We had plenty at home.
OUGHT TO
Advice You ought to thank her.
Assumption Anne ought to be at home by now.
Obligation We ought to protect the environment.
You ought to have told me earlier. Why didn't you tell me?
SHALL
Formal rules and regulations, commands Visitors shall be accompanied at all times by a security guard.
You shall not kill.
Offers Shall I copy this document for you?
Suggestions Shall we throw a party sometime next week?
SHOULD
Advice You should smoke less.
Assumption I should get back before 9.
I have never tried setting up a website, but it shouldn't be too difficult.