English Grammar: Ability, Probability, Deduction, Obligation, Permission, Advice, and Suggestions

Ability: Can - Could - Be Able to

We use 'can' and 'could' to talk about a skill or ability. She can speak six languages - My grandfather could play golf very well. I can't drive - I won't be able to drive that lorry.

Probability: May, Might (something is possible)

He may be in his office (perhaps) (may not) - John might not be in his office (mightn't)

When talking about possible plans, I may (might) be going to Italy in July (it's possible) - I may (might) go to Italy in July (it's possible)

Deduction: Can't Be - Must Be

It's snowing, so it must be very cold outside - This bill can't be right (£200 for two cups of coffee!)

Obligation: Must (possibly based on the speaker's opinion)

Children must do their homework - We have to wear a uniform at work (I've got to wear uniform)

Mustn't (prohibition, it's necessary that you do not do it)

You mustn't be late - You mustn't eat in the classroom, you are not allowed

Don't Have to

I don't have to wear a suit to work

Advice - Should / Shouldn't

Giving advice

Students should study for exams in advance - You shouldn't be late to school

Giving an opinion

I think the government should do something about education

Permission, Invitations, Offers, and Requests

We can use verbs such as 'can', 'could', and 'may' to ask for and give permission. We also use modal verbs to say something is not allowed.

Asking PERMISSION: To give PERMISSION

Could I leave early today, please? - You can (may) go out this weekend - You may not use the car tonight - Can we swim in the lake? - Do you think I could borrow your bike?

Offering to do things:

Can I help you, María? - Can I get you a cup of tea? - I will open the door for you

Offering and Inviting:

Would you like a cup of coffee? - Would you like to come home for dinner? - I'd like (I would like) (polite way of saying what you want)

Needn't (it is not necessary to do something)

You have plenty of time. You needn't hurry (You don't need to hurry / There is no need to hurry) - You needn't give me your homework right now - Need I say more? I'd like you to stay

Suggestions

Why don't we watch a film tonight? - What about watching a film tonight? - How about watching a film tonight? - Let's watch a film tonight! - We could watch a film tonight