$11.$ I asked Tam If she wanted to visit the Great Wall in china. 

$12.$ The boys said that they had to try their best to win the match.

$13.$ He asked Mary If she could lend him some money.

$14.$ Hung said that he often went to English speaking club at weekend.

$15.$ The teacher asked his students to study hard for their entrance exam.

$16.$ I advised Peter not to spend too much time on playing games.

$17.$ The fishermen said that they were keen on setting out to sea again.

$18.$ Lan told me that she was waiting for her parents then.

$mien$

11. I asked Tam if she wanted to visit the Great Wall in China. 

12. The boys said that they had to try their best to win the match.

13. He asked Mary if she could lend him some money.

14. Hung said that he often went to English speaking club at weekend.

15. The teacher asked his students to study hard for their entrance exam.

16. I advised Peter not to spend too much time on playing games.

17. The fishermen said that they were keen on setting out to sea again.

18. Lan told me that she was waiting for her parents then.