----- Nội dung ảnh ----- Bài 9: Điền động từ khuyết thiếu "must" hoặc "mustn't" vào chỗ trống.
1. You ___ be late. 2. You ___ tidy up your room. 3. I ___ smoke. 4. You ___ be home by 9 o'clock. The film starts at 9:15. 5. We ___ do your homework. 6. Passengers ___ finish this essay today. It has to be handed in by tomorrow. 7. You ___ play with fire. 8. This is a dangerous tour. Children ___ be accompanied by an adult. 9. People ___ stand on this bus. 10. You ___ cheat in a test. 11. You ___ do more exercise to stay fit. 12. There ___ turn the music too loud. 13. There ___ be something wrong with the engine of this car. 14. We ___ help in the house. 15. You ___ give up when we are so close. 16. You ___ annoy your little sister. 17. This was a nice evening. We ___ meet again. 18. You ___ bite nails.