1. Peter didn't study hard, so he failed the exam
2. Everyone felt tired and hungry, so they sat down under the tree and had a snack
3. Nam is ill; therefore, he isn't here
4. I didn't have enough money, so I couldn't go to China
5. Peter didn't study hard; therefore, he failed the exam
6. I can't buy this bike because/since/as I don't have enough money
7. Nga went to bed early because/since/as she was sick
8, 9, 10: sử dụng because/since/as giống 2 câu trước, bạn tự làm nốt nha
11. He has managed to pass the test though he has been absent frequently
12. Jane has promised not to tell me the secret, but she did that
13. Fred wants to buy a ticket for the drawing even though he knows he will not win the prize
14. My girlfriend insists on going to the circus every Sundays even though the prices are high
15. Mr. Allen is on a diet; however, he ate the chocolate cake
16. It rained, so we couldn't go to school


