- general ability in the present or future - She can play the piano beautifully.
- informal request - Can you help Johnny with his homework?
- informal permission - You can go home now.
- something hard to believe - He can't be 50! He looks much younger.
- lack of ability - I can't open that tin.
- general ability in the past - My grandfather could ride a horse when he was younger.
- possibility - I don't know where she is. She could be at home.
- polite request - Could I use your phone, please?
- lack of ability in the past - I looked everywhere but couldn't find my keys.
- general ability (in all tenses) instead of can
- I haven't been able to finish that report yet.
- They will soon be able to buy a new car.
- specific ability in the past despite difficulties (Can can't be used)
- They were able to cross the river despite the stormy weather.
- She was able to get the job although she didn't have any previous experience.
