----- Nội dung ảnh ----- 10. Without your help, I wouldn't have succeeded this project. b) Mixed practice: 1. Why don't study hard? 2. Keep silent or you'll wake the baby up. 3. I don't know the answer, so I can't tell you. 4. We got lost because we didn't have the map. 5. My friend was so late, so he missed the train. 6. This car is too heavy for me to move. 7. Morning exercises make me feel healthy. 8. The church bells keep me from sleeping. 9. Without air, we would die. 10. I advise him to stop smoking. 11. Be calm, or you'll make a wrong decision. 12. Without a visa, he couldn't have come to that new country. 13. Today isn't Sunday, so the students don't go swimming. 14. Because you don't leave immediately, I call the policeman. 15. I don't know her number, so I don't ring her up. 16. Go right now or you will be late for the train. 17. As she is often absent from class, she can't keep pace with her classmates. 18. I couldn't write to Alice because I didn't know her address. 19. The heavy rain kept everybody from going outdoors. 20. I didn't watch TV last night because I was busy. 21. People don't see the UFO, so they don't call the National UFO Reporting Center.