I/
1. Whom -> whose
2. The fastest -> fastest
3. To who -> To whom
4. Don't -> didn't
17. If you didn't encourage me , I wouldn't learn to swim.
18. Had they seen the sign, they wouldn't have missed the turn.
19. They asked me to say hello to Jim.
20. He wanted to know if she knew Robert.
21. She said that she had been waiting for the bus when he had arrived.
22. Betty wanted to know when I had come.
23. Elisabeth asked me if I had watched the latest film.
24. Anne asked if she had to do the shopping.
