Bài 9: Điền động từ khuyết thiêu "must" hoặc "mustn't" vào chỗ trống. 1. You……………tidy up room. 2. It’s late. You ……………make so much nosiy. 3. You……………smoke. 4.We……………be home by 9 o’clock.The film starts at 9:15. 5. You …………… do your homework. 6. I …………… finish this essay today. It has to be handed in by tomorrow. 7. Passengers…………… talk to the driver whist the bus is in motion. 8.You …………… play with fire. 9.This is a dangerous tour. Children……………e accompanied by an adult. 10.You…………… behome on time. 11. People …………… stand on this bus. 12. You…………… cheat in a test. 13.We …………… do more exercise to stay fit. 14. You…………… turn the music too load. 15. There …………… be something wrong with the engine of this car. 16.You…………… help in the house. 17. We …………… give up when we are so close. 18. You…………… annoy your little sister. 19. This was a nice evening. We……………meet again. 20. You……………bite nails.