Can and can’t sentences in English
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Can in English
Can expresses a possibility, a capacity, or the ability of the subject, or a permission.
Can’t (or cannot, in a single word) is its negative form and expresses a disability. In the interrogative form, Can… must be placed at the beginning of the sentence.
1. Express an ability or inability
Can and can’t are used to say that something or someone may or may not be able to do something:
- He can sing.
- She can speak Japanese fluently.
- I can’t swim.
- Can you play the guitar?
- I’m afraid I can’t come to work on Wednesday.
2. Express an opportunity or occasional characteristics
In this case, it is used in the affirmative form:
- The river can be dangerous at times.
- It can get hot there during the day.
- I know she can win the competition.
- I think your drone can be repaired.
3. To give or request permission or service
Can’t can also be used to deny permission:
- You can use my car if you want.
- Mum, can I go out now?
- Can I ask you a question?
- Can I carry your luggage for you?
- You can go to the swimming pool if you like.
4. Indicate a prohibition with can’t
- You can’t smoke in the restaurant.
- We cannot park the car next to this fire hydrant.
- You cannot drive a car without a license.
5. Express a strong certainty with can’t
In this case, can’t is used to show that you are surprised, or that you are sure that something is wrong in the present or in a past situation, whether it is a past fact or an activity (the construction is different in both cases):
- It can’t be possible!
- He can’t have been to Japan. (construction: can’t + have + verb at the past participle)
- He can’t have been drinking, he looked sober. (construction: can’t + have been + ing)
6. Can and perception verbs
We often use can in front of perception verbs: hear, see, smell, touch…
- I can hear you but I can’t see you!
- We can see the beach from our hotel.
- I can smell something burning.
Could is the preterite of can. It is considered more polite or formal in a request:
- Could I have more tea, please?
8. Can or be able ?
We use be able to when can is impossible to use:
- I’ve never been able to sing.
- I’d like to be able to forgive you.
- Sorry for not being able to help you.