Costumbres y tradiciones en america latina
The use of modals
Modal auxiliaries are followed by bare infinitives. Mind you, the infinitive is not the first form of the verb. The first form of the verb is only one type of the infinitive (it is the simple infinitive).
Johnny could go home after class. (simple infinitive)
You must be joking. (continuous infinitive)
He may have caught the train. (perfect infinitive)
Jimmy must have been sleeping. (perfect continuous infinitive)
That could be the reason why he missed the film. (simple infinitive)
Very often we refer to the past with a present modal and a perfect infinitive:
You should have eaten more. (Present modal + perfect infinitive = past reference)
For the sake of convenience we refer to modal …ver más…
Not necessary to do something (more used than needn’t) e.g. You don’t need to come to the party if you don’t want to.
Strong advice (less used than should) E.g. you’d better do the washing up now.
E.g. I’d better not go out tonight, because I have to get up early tomorrow.
have (got) to
Necessity, impersonal, not for personal feelings, but for a rule or situation. If you are unsure whether to use must or have to, it is usually safer to use have to.
E.g. I have to get up early tomorrow to catch the train to the office.
To express although in clauses
E.g. I may be married to you, but that doesn’t give you the right to treat me like dirt.
Possibility or uncertainty (formal)
E.g. there may be a cure for AIDS within the next ten years.
Asking for and giving permission (less usual, more formal)
e.g. “May I use your phone?”
“Yes, of course you may”
may as well/might as well
Describes the only thing left to do, something which the speaker is not enthusiastic about
E.g. I’m so bored, I may as well do some housework.
Possibility or uncertainty
E.g. there might be a cure for AIDS within the next ten years.
E.g. If I knew her better, I might invite her to the ball.
When you feel sure something is true (opposite of can’t)
E.g. The tennis match must be over by now. (I’m sure it is).
Necessity, personal feelings e.g. I