Probability

Learn about modal verbs for possibility, impossibility and certainty and do the exercises to practise using them.

Level: beginner

Possibility

We use may, might and could 

to say that something is possible,

 but not certain:

They may come by car.

 (= Maybe they will come by car.)
They might be at home.

 (= Maybe they are at home.)
If we don't hurry, we could be late.

 (= Maybe we will be late.)

We use can to make

 general statements

 about what is possible:

It can be very cold here in winter. 

(= It is sometimes very cold here in winter.)
You can easily get lost in this town.

 (= People often get lost in this town.)

Be careful!
We do not use can to talk about specific events: A: Where's John? B: I'm not sure. He may/might/ could be (NOT can) in his office. Notice the difference in meaning  between can and may/might/could: That dog can be dangerous. (= Sometimes that dog  is dangerous. I know.) That dog may/might/ could be dangerous. (= Perhaps that dog is  dangerous. I don't know.)