17. She asked if I could help her.

- Câu tường thuật với Yes/No - question:

S + asked + (O) + if/whether + S + V (lùi thì)

*Đổi ngôi: you -> I, me -> her

18. They said (that) I had to wash my hands.

- Câu tường thuật với câu khẳng định: S + said + (that) + S + V (lùi thì)

*Lùi thì: must -> had to

*Đổi ngôi: You -> I; your -> my

19. They said (that) it wouldn't rain the next day.

*Lùi thì: won't -> wouldn't

*Trạng từ: tomorrow -> the next day

20. He said (that) he should learn Spanish.

*Đổi ngôi: I -> he

21. He said (that) he couldn't drive a lorry

*Đổi ngôi: I -> he

*Lùi thì: can't -> couldn't

22. He asked if I would have dinner with him.

*Lùi thì: will -> would

*Đổi ngôi: you -> I; me -> him

23. He asked if he should carry my suitcase.

*Lùi thì: shall -> should

*Đổi ngôi: I -> he; your -> my