Exercise 24. Use the verb can/could or to be able to in the correct form followed by the appropriate infinitive
1. Have you a friend you ... (to trust)?
2. He ... not (to see) me. I came when he had gone.
3. ... you (to call) a little later? I’m afraid I'll be busy till 7.
4. He's not answering the phone. He ... not (to get) home yet.
5. She ... not (to forget) your address; she has visited you several times.
6. You ... (to join) her much later if she wants you to go to the yacht.
7. My cousin ... not (to do) it. I don't believe it.
8. I ... (to help) him but I didn't know he needed help.
9. Your English is quite good for a beginner. You ... (to read) English books in the original.
10. If your friends are planning to go to the country you ... (to go) with them.
11. He ... not still (to write) his composition. The teacher has already left the classroom.
12. I don't believe a single word of his; he ... not (to fail) to learn the news before us.
13. It ... not (to be) a joke. He means it.
14. ... you (to pass) me the bread, please?
15. Look! I ... (to lift) this chair with one hand.
16. It wasn't easy but our team ... (to win) the match.
17. She was sitting with her back to me, so I... not (to see) her face.
18. He has no idea what the book is about. He ... not (to read) it very carefully.
19. ... this old woman (to be) Laura? She ... not (to change) so much.
20. The situation was bad but it ... (to be) even worse.