1. "I am going to play tennis tomorrow" she said

=> She said she was going to play tennis the next day.

2. "We go to school by bike", said Ba

=> Ba said they went to school by bike.

6. Hurry up or you can't catch the last bus

=> If you hurry up, you can catch the last bus 

7. He loses his job because he is late every day

=> If he was early everyday, he wouldn't lose his job

8. I'll call the police if you don't leave me alone

=> Unless you leave me alone, I'll call the police.

10. If we don't hear from you within seven days, the order will be cancelled

=> Unless we hear from you within seven days, the order will be cancelled

11. David had gone home before we arrived

=> After David had gone home, we arrived

12. We had lunch then we took a look around the the shops

=> Before we took a look arround the shops, we had lunch

13. I started learning English 10 years ago

=> I have learned English 10 years ago

14. I last saw him when I was on bussiness in Hai Duong

=> I have seen him since I was on bussiness in Hai Duong

15. It was cold. However, Tom still went swimming. (although)

=>Although it was cold, Tom still went swimming

16. John is very sad. He fails the final exam. (because)

=>John is very sad because he fails the final exam.