ملخص 2A Grammar: Modal and related verbs، اللغة الإنجليزية المتقدمة

القوانين والتعريفات والأفكار الأساسية في الموضوع، من الكتاب المقرّر. راجعها داخل TawjihiAI مع البطاقات والأسئلة.

We use modal auxiliary verbs and phrases to convey the attitude of the speaker to an event.

We use must/have to to talk about what is right or necessary.
To express a strong obligation coming from the speaker, we use must or have got to: I must/have got to do my homework.
To express a strong obligation coming from an external authority, we use have to or be required to: You have to/are required to obey the law.
To express a negative obligation or prohibition, we use mustn’t or can’t: You mustn’t/can’t cheat in an exam. (it’s wrong)
To express lack of obligation or necessity, we use needn’t, don’t need to or don’t have to: You needn’t/don’t need to/don’t have to write this essay. (but you can)
didn’t need to or didn’t have to mean it was not necessary to do something. The action may or may not have taken place. I didn’t need/have to learn the poem by heart. (so I didn’t)
Needn’t have means someone did something and later discovered it was not necessary. It indicates regret or relief. I needn’t have learnt the poem by heart. (but I didn’t know that, so I did)

We use verbs like be required to / be obliged to in all tenses to refer to an ‘outside authority’ that gives orders or sets rules:
He was required to get proper qualifications.
We are obliged to come to school on time.

To express an advisable, but not obligatory action, we use should, ought to or had better. You should/ought to/had better tell your friend the truth.
For the past, we use should and ought to, but not had better. They suggest the action was not fulfilled.
You ought not to have painted the wall blue. (but you did)
We can use might or could for an advisable yet probably unfulfilled action, but we have to stress the main verb, not the modal verb. She might/could say something. (but she probably won’t)
You might/could have told me. (but you didn’t)

We use be supposed to to talk about what should/shouldn’t happen according to rules or according to what is generally expected. It is not used in continuous tenses:
They are supposed to be free.
Animals are not supposed to suffer like this.

To express ability, we use can and be (un)able to: I can’t/am unable to give you my phone.
To express a general ability over a period of time in the past, we use could or be able to: He could/was able to climb trees when he was younger.
To express the ability to perform a specific action in the past, we use be able to or managed to, but not could
We can use couldn’t in negative sentences:
They couldn’t/weren’t able to/didn’t manage to reach an agreement.
To express a conditional ability, we use could, but not may or might
To express our willingness to do something, we use will and would. The meaning is similar to ‘want to’. We use won’t/wouldn’t to express unwillingness.
Nader will always help you if you need something. He is very kind.
Her friend wouldn’t even text her.

To express how much we believe something from logical deduction we use must, can’t or might.
He must be an actor. (from the way he talks)
She can’t have studied in Sweden. (she doesn’t even know how to say ‘school’ in Swedish)
It might have been a gift. (I suppose she didn’t buy it for herself, she doesn’t like this colour)
To say something is possible, we use could, may or might, but not can.
Adding (very) well shows you think the possibility is stronger. He could/may/might very well have been somewhere else.
-…

Grammar — Modal and related verbs