cho tam giác ABC vuông tại A, AM là đường trung tuyến, D nằm trên AM sao cho M là trung điểm AD a. chứng minh tứ giác ABDC là HCN b. E đối xứng A qua BC chứng minh AE vuông góc ED c. chứng minh tứ giác BCDE là hình thang cân

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Read the following passage and mark the letter A, B or C on your answer sheet to indicate the correct answer to each of the questions. Cities Get Clean by Going Green When people hear the word “city”, they usually imagine concrete, neon signs, and lots of air pollution. Thanks to some clever and concerned architects, this image is starting to change. The concept of green cities aims to bring some beauty from rural environments into urban areas. It is not only about looking better though. Green cities are also trying to improve the efficiency of cities and raise the standard of living for people who stay in them. The term “green cities” refers to cities where builders take into account several environmental factors before those cities are constructed or redesigned to be more physically appealing than traditional cities from the past. In addition, the mobility of citizens should be considered, so public transportation can be more convenient and travel time to work can be reduced. Energy sources should also be evaluated with the goal of minimizing air pollution. When it comes to going green, the city of Barcelona is far ahead of its time. Since 1859, its designers have consciously tried to create sustainable urban designs. Then in 1992, the city received a well-deserved makeover before hosting the Olympic Games. In recent years, Barcelona has upgraded its transportation system. This has reduced air pollution and more workers are using public transportation instead of their own vehicles. Barcelona also boasts one of the best recycling programs in the world. Visitors will find clear, color –coded trash bins throughout the city where they can put all of their materials. It is no secret in Portland, Oregon is one of the greenest cities in the US. Since 1903, it has been an example of what American cities can accomplish with careful planning. Instead of filling its area with office buildings, Portland has plenty of green space for activities. It has 119 kilometers of running, hiking, and bike trails that allow citizens to experience the great outdoors. The city also offers residents creative energy plans that give them the opportunity to pay a bit extra for clean energy sources. For about $3 to $9 extra each month, homeowners can choose solar or wind power and help the environment. These are only a small sample of the green cities around the world. As more people experience the pleasure of visiting green cities, it seems certain that the trend of urban areas going green will continue far into the future. Question28: All of the following are true about Barcelona EXCEPT that . A. it is said by some to have one of the best recycling programs in the world B. more people have used public transportation C. air pollution has been reduced D. visitors can put all their trash in one colorful trash bin. Question 29:How does the author seem to feel about the future green cities? A. We should continue to see more green cities built each year. B. Green cities are too expensive to build in most countries. C. Few people have interest in living in green cities. D. The best green cities in the world are in North America. Question30: Who would enjoy living in Portland most? A. Someone who doesn‟t mind air pollution. B. Someone who wants cheap energy solutions. C. Someone who likes to work in tall buildings. D. Someone who enjoys exercising outside. Question31: The word “they” in paragraph 3 refers to . A. those who run the city B. some dustbins in the city C. people who collect dustbins D. people who want to throw out the trash Question32:What does the term “mobility” in paragraph 2 mean? A. the opinions of people. B. how visitors move around. C. the feelings visitors have D. how much money tourists spend