【南方新课堂 金牌学案】2016-2017学年高中英语选修六（人教版 课件+练习+单元测试）：Unit 5　The power of nature （8份打包）

第五单元过关检测 (时间:90分钟　满分:120分) Ⅰ.阅读理解(共两节,满分40分) 第一节(共12小题;每小题2.5分,满分30分)[来源:学科网ZXXK] 阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。 A (导学号51970073) A sandstorm,known as a dust storm,is exactly what it sounds like:a very strong windstorm,especially in the desert,that carries clouds of sand or dust,and greatly reduces visibility(可见度).This wind is usually caused by convection currents,which are created by intense heating of the ground,and is usually strong enough to move entire sand dunes.Air is unstable when heated,and this instability(不稳定性) in the air will cause the mixture of higher winds with winds in the lower atmosphere,producing strong surface winds. Sandstorms can disturb travels,and sometimes destroy whole roads,and dry flat areas,such as parts of the western United States.Similar dust storms can be found on Mars,and are thought to be seasonal.Today,the destruction of forests and too much farming of farmland can cause a sandstorm problem.Over-grazing and too much use of water resources can also cause sandstorms. In the United States of America,sandstorms are rare because of the lack of large deserts and more importantly the development of proper agricultural techniques.The last recorded destructive sandstorm in American history was the Dust Bowl,one that occurred on July 16,1971 and was widely recorded by meteorologists(气象学家). To protect themselves from sandstorms,some people wear protective suits.Special equipment can be fixed in some cars to prevent sand from getting into the engine.Sand storms can cause coughs,and the sand and dust have also been known to be able to carry “infectious diseases”.Sand particles,unlike dust ones,will block air passages,and cause the person who breathes them in to choke.Dust particles may cause an allergic(过敏的) reaction. 1.Which of the following plays the biggest part in forming sandstorms? A.The instability of the sand. B.The instability of the wind. C.The speed of the wind. D.The intense heating of the ground. 答案:D 解析：细节理解题。根据第一段中的“This w