=>
14. He asked if he could go home then.
15. He said to her that she could come in but she would have to be quiet./He told her that she could come in but she would have to be quiet.
16. He asked (me) what time they would arrive in Cairo.
17. He said that she had to try harder if she wanted to succeed.
18. She said that her father would be angry with her if he found out.
19. He said to her that she shouldn't drive so fast./He told her that she shouldn't drive so fast.
20. He said that he could meet me on Friday./He said that he would be able to meet me on Friday.
21. She said to him that he had better ask his parents./She told him that he had better ask his parents. 
22. He said to her that he might not be able to meet her at the train station.//He told her that he might not be able to meet her at the train station.
Câu tường thuật dạng Yes/No questions : asked sb if S V(lùi thì)
Câu tường thuật dạng WH questions : asked sb + từ để hỏi + S V(lùi thì)
Lùi thì trong câu tường thuật :
HTĐ -> QKĐ
HTTD -> QKTD
Can -> Could
Will -> Would
Must -> Had to
Had better/Should (không đổi)
Shall -> Should/would
May -> Might