Can and Can’t
1) to express ability
I can swim well.
Can you speak English? Yes, I can.
Can he touch-type? No, he can’t (cannot).
Can she drive a lorry?
Can we read Arabic?
Can they fly a plane?
2) to ask or give permission
Can I go out with my friends tonight, please? Yes, you can.
Can we leave early today, please? No, you can’t.
You can go and open a window.
He can play football in the park this afternoon.
She can’t see him any more.
We can’t park here because the road sign says No parking.
They can’t leave their dog in a car while shopping.
3) to make requests and offers
Can you lend me £20, please?
I can call your mum if you want me to.
Can he go out with me, please?
She can do it by herself, can’t she?
We can arrange a holiday for all of us.
Can they let me look after their dog for a weekend, please?
Could and Couldn’t
1) same use as ‚can‘ (less definite in some structures)
I could go and get your shopping for you.
You could lend me your car. Yes, I could.
Could he call me tomorrow evening, please? No, he couldn’t.
She could run fast if she wanted to.
We could go on holiday to Spain this year. ( we still have to decide yes or no)
Could they stop shouting, please? (very polite request)
2) ability in a past
I could speak French when I was younger.
You could play football before the accident.
He could drive before he lost his licence for drink-driving.
She could work for 14 hours in a restaurant when she was 17.
It couldn’t happen when I was a manager here!
We could play tennis for hours when we were in our early 20’s.
Could they speak any English before the language course? No, they couldn’t.
3) Could is also used to say something is/will be possible to happen.
I could start learning English one day, I suppose. (I’m not certain about that).
You could tidy up your room one day.
He could get a better job if he tries.
She couldn’t do it. (it’s impossible for her to do it)
It could rain later. (It’s possible)
Both ‚can‘ and ‚could‘ are “modal verbs“, that means ALWAYS
can/could + verb without ‚to'(bare infinitive).
can speak, can hear, can read, etc.