Let’s continue learning our modals!
I wanted to remind you that the modals don’t change, except “be to,” and “have to.” That is why sometimes we replace the unchanged verb with another one in the past or future. If you will choose the needed modal verb in accordance with your mood or other inner feelings, remember that “have to” replaces the verb “must” in the past or future. So in these cases, the use of both verbs will be similar.
Pay attention! The following modals request an infinitive without “to” after them: can (could), may (might), must, and should.
4) The verb “to have to” is mostly used for duty of necessity or need:
- I had to study a lot to become a teacher.
- To be healthy everyone has to have eight hours’ sleep at night.
- She will have to work hard at her work if she doesn’t learn the rules now.
- They had to give up smoking to treat their cough.
5) We use “be to” when we have a duty or necessity because of some previous agreement; when we have got some instructions; when something will happen with or without our intervention; when we have got a possibility.
- The next course is to start this summer.
- Am I to stay here until you come back?
- You are to meet your friends at the airport this afternoon.
- If we are to study together for six years, we should not be enemies.
6) When we have got any moral imperative, disapproval, confident supposition, a piece of advice, and reproach (only should) we use either should or ought to.
- You should study these rules thoroughly.
- They have studied a lot. They should pass their exams. (They ought to pass their exams.)
- Why should he feel guilty? He is innocent.
- We oughtn’t to have paid the vendor in advance. That was a mistake.