Using modal verbs should, ought to, had better, have to, and must
The modal verbs should, ought, had better, have to, and must are useful for giving advice and for talking about obligations and better ways of doing things. They are close in meaning but differ in strength and attitude of the speaker.
Let's start with should.
1. Should can be used to express a better way of doing something or to give advice.
He should try to attend the meeting because his boss will be there.
In this sentence, should is the modal verb, and attend is the main verb.
The simplest form of a main verb follows a modal verb: He should attend the meeting.
Do not add the third person "s" to a verb after a modal: He should attends the meeting.
Do not use the infinitive verb after a modal: He should to attend the meeting.
2. Should can be used to express a large amount of certainty.
I should be at the meeting on time because I have plenty of time to get there.
3. Should can be a slightly more formal substitute for the conditional word if:
Should you need a ride to our meeting, don't hesitate to give me a call.
4. Should can be used to express regret for past action or inaction.
The past form of the modal should is should have + the past participle:
I should not have missed that meeting with the boss.
You should have attended the meeting because your boss was there.
Note: Ought rhymes with got
Ought to is similar in meaning to should but not used as often and is less formal.
You ought to attend the meeting tomorrow.
Past Tense: You ought to have attended the meeting because your boss was there.
Had better is stronger than should and ought to.
Authority figures such as parents often use had better.
Had better implies an indirect order or a warning.
You had better attend the meeting!
If someone tells you, "You had better attend the meeting," they are not making a polite suggestion. If that someone is your supervisor, it is likely an indirect order or an indirect way of telling you, "Attend the meeting or there will be negative consequences." If that someone is a colleague, it could be a helpful warning: if you don't attend the meeting, you could be in some trouble.
In other words, should you not attend the m