职称英语理工类的A级阅读理解练习(3)

　　The Exploding Lakes of Cameroon 　　What comes to mind when you think of a lake? You probably imagine a pretty scene with 　　very different. For them，lakes may mean terrible disasters. In 1984，poisonous gases exploded 　　years later,Lake Nyos erupted A cloud of gases rolled down the hills and into the valleys and 　　Lake Nyos and Lake Monoun are craterlakes They were formed when water 　　not active anymore. However, poisonous gases from the center of the earth continue to flow up 　　gases are released often because the waterturns overregularly.That is，the water from the 　　However，in Lakes Nyos and Monoun，there is no regular turning over.No one knows the 　　crater lakes. In fact，scientists who have studied Lakes Nyos and Monoun have found 16,000 　　water to turn over suddenly，the gases escape in a violent explosion. 　　to escape disaster. Now scientists from the United States，France，and Cameroon have found a 　　the middle of the lake，with one end of the pipe near the bottom and the other end in the air.Near 　　when the gas pressure gets too high，the holes are opened and some of the gas-filled water shoots 　　less likely.However, the scientists are not sure that one pipe will be enough to prevent explosions.They hope to put in others soon and they plan to install a similar pipe and a computer system at Lake Monoun as well. 　　warning systems at both lakes. If the gas pressure rises to a dangerous level，computers will set 　　have time to escape from the dangerous gases. 　　A Water will flow down the hills 　　C A strong wind will rise from the lakes 　　42 Which of the following statements about Lake Nyos and Lake Monoun is true? 　　B They are at the top of two active volcanoes. 　　D Water in them turns over regularly. 　　A the gases rise to the top and mix with air. 　　C scientists have put in a computer system. 　　44 A team of scientists has 　　B identified the gases at the bottom of the lake 　　D removed all dangerous gases from the lakes 　　A Scientists are planning to install pipes in all crater lakes. 　　C Explosion disasters could be avoided in the future