Phát biểu nào sai khi nhận biết lực ? A: Khi vật bị biến dạng và thay đổi vận tốc, ta có thể kết luận có lực tác dụng vào vật. B: Khi hình dạng của vật thay đổi, ta có thể kết luận có lực tác dụng vào vật. C: Khi vận tốc của vật thay đổi, ta có thể kết luận có lực tác dụng vào vật. D: Khi vận tốc của vật không thay đổi, ta có thể kết luận không có lực tác dụng vào vật.

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REVISION UNIT 9 Choose the one or phrase that best completes each sentence. 1. Some marine animals are dangerous to humans. A. in the mountain B. in the ocean C. in the forest D. in the house 2. The floor was covered in tiny pieces of paper. A. unimportant B. many C. very large D.extremely small 3. We had an accidental meeting with an old friend at the party last night. A. unpleasant B. unexpected C. unlucky D. unacceptable 4. How many offsprings does a sperm whale usually have? A. eggs B. mammals C. calves D. diets 5. He is always interested in the mysteries that lie beneath the blue depths of the ocean. A. over B. under C. above D. on 6. _________is the variety of different types of plant and animal life in a particular region. A. Interaction B. Herbicide C. Environment D. Biodiversity 7. John’s father is a/ an _________scientist. He studies life in the sea. A. marine B. undersea C. submarine D. organism 8. Some tiny organisms are _________along by the currents. A. carried B. taken C. flowed D. moved 9. Sperm whales are _________, which means they eat meat. A. herbivores B. carnivores C. omnivores D. mammals 10. Seventy-five percent of the earth’s _________are covered by sea and oceans. A. face B. flat C. resurface D. surface 11. In some countries, teenagers can live _________from their parents if they want. A. dependently B. independence C. independent D. independently 12. Oil spills are a great _________to the undersea world. A. threat B. threaten C. threatened D. threateningly 13. The teacher had divided the students _________small groups before they did their task. A. of B. for C. into D. in 14. The authority supplied the victims of the fire _________food, clothes, and money. A. on B. for C. to D. with 15. Her work has enormously contributed _________the charity collection. A. for B. on C. to D. in 16. If I _________in your position, I would not accept her offer. A. am B. were C. have been D. would be 17. You should work harder for the coming terminal examination. A. had better B. would rather C. needn’t D. mustn’t 18. Our teacher often advises us that ________ work in order to realize our ambitions. A. you will B. we should C. should you D. should we 19. She suggested that he ________ his situation carefully. A. should consider B. considers C. is considering D. has to consider 20. You ________ Mark. You know it’s a secret. A. should tell B. shouldn’t tell C. couldn’t tell D. might tell 21. What would Tom do if he ________ the truth? A. would know B. has know C. knows D. knew 22. ________ you, I would think twice about that decision. It could be a bad move. A. If I am B. Should I be C. If I were D. If I had been 23. That sounds like a good offer. I ________ if I ________ you. A. had accepted/were B. will accept/am C. would accept/were D. accepted/were 24. If energy ________ inexpensive and unlimited, many things in the world would be different. A. is B. were C. had been D. would be 25. If I ________ wings, I ________ take an airplane to fly home. A. have/won’t have to B. had/wouldn’t have to C. have/will have to D. had/didn’t have to 1. I don't know enough about the machine, so I can't mend it myself. __________________________________________________________________ 2. I don't ride the bus to work every morning because it's always so crowded. _________________________________________________________________ 3. Not enough money is spent on cancer research, so a prevention has not been found. _________________________________________________________________ 4. The wind is blowing hard. so I won't take the boat out for a ride. _________________________________________________________________ 5. Nick can't find the way because he hasn't got a map. _________________________________________________________________ 6. Mary ignores Lucy. so she gets angry at him. _________________________________________________________________ 7. We don't visit our parents very often because they live so far away. _________________________________________________________________ 8. Linus is smart, so he finds clever solutions to life's problems. _________________________________________________________________