To express ability, possibility, permission or obligation. They are only complementary verbs, they need another verb so that the sentence makes sense.
Modal verbs do not function without another verb, which is generally written in the infinitive form after the modal. You will find the different types of Modals with Examples, Exams and Downloads.
It is used to express ability or opportunity, to request or offer permission and to show possibility. The negative form of 'Can' is Can't.
I can speak French.
We can go to the cinema this weekend.
I can't help you.
Can you give me those bags?.
You can leave now.
The past form of 'Can' is 'Could'. We can use 'be able to' instead of 'Can' to talk about the past or the future.
She was able to run fast when she was young.
She could run fast when she was young.
Cars will be able to fly in the future.
They were able to win a game in the 90's.
It is used to talk about an ability in the past. We can also use 'was/were able to' instead of 'Could'. The negative form of 'Could' is 'Could not' and its contraction is Couldn't.
Tom could jump higher 10 years ago.
Tom was able to jump higher 10 years ago.
I could run a marathon in my twenties.
She couldn't sleep well when the baby was born.
It can be used to talk about a possibility or probability.It is also used to make suggestions and requests.
Rose could help you if you want to.
I could go with you.
It could rain tomorrow.
Could you close the door, please?
It is used to talk about possibility. It can also be used to talk about a possibility in the future, like the modal 'Could'. The negative form of 'May' is 'May not'.
It may rain today.
We may go to the cinema.
It may not be good.
It may snow tomorrow.
Emma may want to have a drink now.
'May' can be used to give permission or instructions. In the interrogative form, the use of 'May' sounds more polite than 'Can' or 'Could'.
You may use your cell phone now.
She may arrive at 10 p.m.
May I have a coffee?
May I leave now?
'Might' is another Modal verb with the same meaning as 'May' but the last one indicates more certainty or probability.Take into account that we also use 'Might' instead of 'May' to talk about the Past.The negative form of 'Might' is 'Might not'.
He might have gone out last Saturday.
They might visit you tonight.
She might win the race.
You might try tomorrow.
It is used to talk about the future, to make promises and offers, to express spontaneous decisions, plans and predictions.
The past form of 'Will' is 'Would'.
Its negative form is 'Will not' and the contraction is Won't (it is more used).
I will help you with those bags.
We will go on vacations next summer.
I will go with you.
I will use the stairs.
I won't tell anyone, I promise.
Cars will fly by 2050.
'Shall' has the same meaning as 'Will' but it is more formal, so we use 'Shall' to talk with a superior, an unknown person or an authority.
It is common to use 'Shall' when we want to ask for advice or an opinion.
The negative form of 'Shall' is 'Shall not'.
Shall I tell her?
I'm cold. Shall I close the window?
I shall never forget you.
He shall not be fired.
'Should' and 'Ought to' have a very similar meaning. We use them to talk about obligations and recommendations.
We write 'Should' and 'Ought to' followed by the infinitive form of the verb. Their negative forms are Shouldn't and Oughtn't.
You look tired, you should go to bed.
They should do it now.
It should be cloudy tomorrow.
You shouldn't eat sweets before dinner.
You ought to study every day.
He oughtn't call her like that.
He shouldn't call her like that.
There are some subtle differences between 'Should' and 'Ought to'.
'Should' is often used to give advice while 'Ought to' has to do with moral duty.
Take into account that 'Should' is more commonly used, especially in the negative or interrogative form.
You should tell him the truth.
Emma shouldn't go out so late at night.
You ought to visit your grandpa more often.
Should I call the doctor?
Children ought to respect old people.
'Must' and 'Have to' are quite similar, they are used to talk about obligations and they are followed by the infinitive form of the verb.
There are some differences in meaning, we use 'Must' to express personal opinions about what should be done, instead,'Have to' is used to express an external obligation imposed by someone else.
We use 'Must' to talk about a probability or to assume something.
I must brush my teeth every day.
John must be at home.
Imposed by the law:
You have to use the seatbelt when driving.
We must leave now.
Expressing that it was imposed by an authority:
They have to study a lot for tomorrow.
It is said by the teacher:
You must study for tomorrow.
The negative form of 'Must' is Mustn't. The negative form of 'have to' depends on the subject, Don't/Doesn't have to.There are differences in meaning.
We use Mustn't to talk about prohibitions but we use Don't/Doesn't have to when there is lack of obligation.
You can also use 'Must' to ask rhetorical questions.
There is no necessity:
I don't have to cook dinner.
You mustn’t smoke in public areas.
Lack of obligation:
You don't have to come if you don't want to.
Must she talk to you in that way?
'Would' is used to talk about the past or about the future in the past, it is the past form of 'Will'. We also use 'Would' in the Conditional sentences.
It is also used to express desire, opinions or making polite requests.
We generally write 'Would' followed by the main verb in the infinitive form.
Future in the past:
Last Saturday I would have gone with you.
I would call Tom if I were you.
Would you help me with the shopping bags, please?
Would you like to go to the theatre?
If I had money I would buy a plane.
The short form of 'Would' is 'd'. Its negative form is Wouldn't.
If I had my wallet, I'd pay for the pizza.
I wouldn't go there.
She'd work harder if she had time.
We wouldn't eat that.
He'd like to go to New Zealand some day.