=>

21. He asked me why I enjoyed reading books.

22. He asked them how they operated that machine.

23. He asked me why I studied English.

24. I asked her who was writing that letter.

25. I asked my mother what they would buy for dinner.

26. He asked me how much money I had.

27. He asked her how he decided that problem.

28. I asked her where her house was.

29. I asked her what I should do in that situation.

30. He asked me who would help him that work.

Câu tường thuật dạng WH questions: asked sb + từ để hỏi + S V(lùi thì)

Câu tường thuật -> lùi thì

HTĐ -> QKĐ

HTTD -> QKTD

Will -> Would

Should (không đổi)