| A dam is a man-made structure built across a river. Most dams are built to control a river’s water flow, improve navigation and control flooding. However, some dams are built to produce hydro-electric power. Hydro-electric power is produced as water passes through a dam, and into a river below. The more water that passes through a dam, the more energy is produced. Once a dam is built, a man-made lake is created behind the dam. Electricity is produced by a kind of equipment called a turbine(水轮机). Turbines contain metal coils(线圈) surrounded by magnets(磁铁). When the magnets move round rapidly over the metal coils, electricity is produced. Turbines are located inside dams. The falling water makes the magnets go around the coils. Dams provide clean energy, but they can also harm the environment. Species that use rivers to reproduce are often hurt by dams. In the Northwest of the US, the population of fishes has dropped from 16 million to 2.5 million since hydro-electric plants were built on the Columbia River. Dams all over the world have hurt some species. The highest dam in the world is the Nurek Dam on the Vakhsh River in Tadzikistan, a country in central Asia. This dam is 300 meters tall. 1. Which of the following statements is NOT true according to the passage? A. Some dams are built for controlling a river’s water flow. B. Hydro-electric power is usually produced through a dam. C. Dams can offer energy and they are harmless to the environment. D. Generally speaking, where there is a dam, there is a man-made lake. 2. The third paragraph mainly tells us _____. A. how hydro-electric power is produced B. What a turbine is and how it works C. how the magnets and the metal coils work D. how the falling water passes through a turbine 3. The dam which controls the Colorado river is ____. A. the Oroville Dam B. the Hoover Dam C. the Nurek Dam D. the Vakhsh Dam |
目前街头出现了越来越多的猫与狗，对此“中学生英语报”组织了一场讨论：城市内是否可以饲养宠物。请你根据下表提供的信息，介绍讨论情况，并说明自己的观点和建议。
| 支持饲养宠物 | 反对饲养宠物 | 你的观点 |
| 1． 安慰孤寡老人 2． 人与动物和谐相处，增添生活情趣 | 1． 造成环境污染 2． 吵闹声，甚至伤人 | …… |
注意：1．词数100左右。2．可以适当增减细节，以使行文连贯3．开头语已为你写好。
Recently we have had a heated discussion on whether people should keep pets at home in cities.