Ability: advanced points
Future: can or will be able
We use can to talk about future actions which we will be able to do because of present ability, present circumstances, present decisions, etc.
- She can win the race tomorrow if she really tries.
- I’ve bought the tent, so we can go camping next weekend if we want to.
- I haven’t got time today, but I can see you tomorrow.
- Can you come to a party on Saturday?
In other cases we prefer other structures, for example will be able to.
- I’ll be able to speak French at the end of this course. (not
I can speak French …) - One day people will be able to go to the moon for the weekend. (or it will be possible to go …)
could in the past
Could is not normally used to say that somebody did something on one occasion in the past (see here).
- I managed to buy a really nice coat yesterday. (not
I could buy a really nice coat yesterday.)
However, could can refer to one occasion with certain verbs: see, hear, taste, feel, smell, understand, remember and guess (see here).
- I could smell something burning.
- I could understand everything she said.
And we can use could to talk about one occasion with words like hardly or only, that have a negative sense.
- She could hardly believe her eyes.
- I could only get six eggs.
Could can also sometimes refer to one occasion in subordinate clauses.
- I’m so glad that you could come.
Languages and instruments: She speaks Greek.
We often leave out can when we are talking about the ability to speak languages or to play instruments.
- She speaks Greek. / She can speak Greek.
- Do/Can you play the piano?
can/could always
Can/could always can mean ‘can/could … if there is nothing better’.
- ‘I don’t know what to get Mark for his birthday.’ ‘Well, you can always give him a gift card.’
- ‘What are we going to eat?’ ‘We could always warm up that soup.’