题目

把动力装置分散安装在每节车厢上，使其既具有牵引动力．又可以载客，这样的客车车辆叫做动车．而动车组就是几节自带动力的车辆（动车）加几节不带动力的车辆（也叫拖车）编成一组，就是动车组．假设动车组运行过程中受到的阻力与其所受重力成正比，每节动车与拖车的质量都相等，每节动车的额定功率都相等．若l节动车加3节拖车编成的动车组的最大速度为30m/s；则6节动车加2节拖车编成的动车组的最大速度为 A.80m/s      B.90m/s      C.100  Many cities around the world today are heavily polluted. Careless methods of production and lack of consumer demand for environment friendly products have contributed to the pollution problem. One result is that millions of tons of glass, paper, plastic, and metal containers are produced, and these are difficult to get rid of. However, today, more and more consumers are choosing “green” and demanding that the products they buy should be safe for the environment. Before they buy a product, they ask questions like these: “Will this shampoo damage the environment?” “Can this metal container be reused or can it only be used once?” A recent study showed that two out of five adults now consider the environmental safety of a product before they buy it. This means that companies must now change the way they make and sell their products to make sure that they are “green”, that is, friendly to the environment. Only a few years ago, it was impossible to find green products in supermarkets, but now there are hundreds. Some supermarket products carry labels to show that the product is green. Some companies have made the manufacturing (生产) of clean and safe products their main selling point and emphasize it in their advertising. The concern for a safer and cleaner environment is making companies rethink how they do business. No longer will the public accept the old attitude of “Buy it, use it, throw it away, and forget it”. The public pressure is on, and gradually business is cleaning up its act. 1.It is clear from the text that the driving force (动力) behind green products is____. A. public caring for the environment                   B. rapid development of companies C. new ways of doing business                          D. rapid growth of supermarkets 2.The underlined word “it” in Paragraph 4 refers to_________. A. the selling point                              B. the company’s product C. a great demand for healthful goods              D. the manufacturing of green products 3.What would be the best title for the text? A. Business and people                            B. Shopping Habits Are Changing C. Business Goes Green                                   D. Supermarkets and Green Products