1. You can do it alone/by yourself.
2. I can't go tonight.
3. They can't come to the meeting.
4. I couldn't do it last night.
5. Could you tell me what happened?
6. I couldn't do it so fast.
7. We'll be able to do it on Monday, I think.
8. They will be able to come with you.
9. Could you speak English when you were a child?
10. Perhaps we could go to Paris this weekend.
11. She could speak several languages.
12. Could you type this letter?
13. We could go tomorrow.
14. We'll go as soon as we can.
15. Will you be able to come in time?
16. I don't know if I'll be able to.
17. Could you fill in this form?
18. They couldn't catch the train.
19. Can you swim?
20. No, I can't swim very well.
21. I haven't been able to do it yet.
22. Marian hasn't been able to finish in time.
23. I could do it for you.
24. We could go shopping this afternoon.
25. We haven't been able to come before.
26. She couldn't cook very well.
27. Can't the little girl walk yet?
28. Can you speak French?
29. I haven't been able to sleep lately.
30. I looked for the book but I couldn't find it.
31. When I was 17 I could run 100 metres in 11 seconds.
32. I could hardly understand what he was saying.
33. My grandfather was a seaman but he couldn't swim.
34. The child fell into the river but we were able to rescue him.
35. My grandmother could play the piano very well.
36. We could go to Scotland on holiday.
37. I haven't been able to do my homework yet.
38. Why don't you apply for the job? You could get it.
39. We haven't been able to help him.
40. If you come to London you could stay with us for a few days.