.

Subsequently, one may also ask, which form of verb is used with had better?

Had better is always followed by a verb in the infinitive without 'to': You had better BE on time. You must or should be on time. Had better is ALWAYS formed from the auxiliary verb 'have' in the past simple ('has better' or 'will have better' do not exist!).

what is the use of have to in English? have to, must. Have to is NOT an auxiliary verb (it uses the verb have as a main verb). We include have to here for convenience. Must is a modal auxiliary verb.

One may also ask, would better VS had better?

"You had better study hard, or you will be in big trouble." "You had better study hard - you will be in big trouble, if you don't." "You had better study hard - you would be in big trouble, if you didn't."

How do you use had?

"Had" is the past tense of these two verbs. In the present tense, "have" is used for I, you, we, and they and all plural nouns. "Has" is used for he, she, and it, and for all singular nouns. ("Has" is the third person singular form of "have.")