Many people still believe that natural resources will never be used up. Actually, the world’s energy resources are limited. Nobody knows exactly how much fuel is left. However, we also should use them economically and try to find out alternative sources of power. According to Professor Marvin Burnham of the New England Institute of Technology, we have to start conserving coal, oil and gas before it is too late; and nuclear power is the only alternative.However, many people do not approve of using nuclear power because it’s very dangerous. What would happen if there was a serious nuclear accident? Radioactivity causes cancer and may badly affect the future generations.The most effective thing is that we should use natural resources as economical as possible. 49. Many people still believe that natural resources will never be ________ A. reduce B. rised C. run out of D. raised 50. According to the writer , we should use energy resources ________ A. economically B. regularly C. financial D. less 51.The word “ approve” in the passage is closet in meaning to ____________ A. disagree B. agree C. improve D. explain 52. ___________ causes cancer and may badly affect the future generations. A. Coal B. Fuel C. Radioactivity D. Electricity 53. Which of the following is NOT true about nuclear power ? A. unsafe B. safe C. risky D. dangerous Choose the sentence (A, B, C or D) that is closet in meaning to the correct sentence. 54. I can't understand him because he speaks so quickly. A. If I can understand him, he can speak so quickly. B. If he doesn't speak so quickly, I can understand him. C. If he spoke more slowly, I could understand him. D. If I understood him, he could speak more slowly. 55. Although he took a taxi, he still arrived late for school. A. In spite of he taking a taxi, he still arrived late for school. B. In spite taking a taxi, he still arrived late for school. C. Despite of taking a taxi, he still arrived late for school. D. In spite of taking a taxi, he still arrived late for school. 56. Global warming has caused many natural disasters. A. Many natural disasters have been caused by global warming. B. Many natural disasters have caused by global warming. C. Many natural disasters have be caused by global warming. D. Many natural disasters caused by global warming. 57. As soon as we got on the plane, the pilot told us to get off again. A. We had just got on the plane when the pilot had told us to get off again. B. We had just got on the plane before the pilot told us to get off again. C. The pilot had told us to get off again before we got on the plane. D. The pilot told us to get off again before we had got on the plane. 58. "We don't open the laboratory today," Mr. Minh said. A. Mr. Minh said that we don't open the laboratory today. B. Mr. Minh said that they don't open the laboratory today. C. Mr. Minh said that they didn't open the laboratory that day. D. Mr. Minh said that we didn't open the laboratory that day. 59. The water temperature increases. Some aquatic creatures are unable to reproduce. A. If the water temperature increases, some aquatic creatures are unable to reproduce. B. If the water temperature will increase, some aquatic creatures would be unable to reproduce. C. If the water temperature won't increase, some aquatic creatures are unable to reproduce. D. If the water temperature didn't increase, some aquatic creatures would be able to reproduce. 60. My English teacher is leaving. His lectures are very interesting. A. My English teacher, is leaving, whose lectures are very interesting. B. My English teacher, whose is very interesting lectures, is leaving. C. My English teacher, whose lectures are very interesting, is leaving. D. My English teacher, who lectures are very interesting, is leaving.