大学英语四级阅读单选题讲解：是非题（4）

　　Passage 4

　　Although April did not bring us the rains we all hoped for,and although the Central Valley doesnt generally experience the atmospheric sound and lightning that can accompany those rains, its still important for parents to be able to answer the youthful questions about thunder and lightning.

　　The reason these two wonders of nature are so difficult for many adults to explain to children is that they are not very well understood by adults themselves. For example,did you know that the lightning we see flashing down to the earth from a cloud is actually flashing up to a cloud from the earth? Our eyes trick us into thinking we see a downward motion when its actually the other way around. But then, if we believed only what we think we see, wed still insist that the sun rises in the morning and sets at night.

　　Most lightning flashes take place inside a cloud,and only a relative few can be seen jumping between two clouds or between earth and a cloud. But, with about 2,000 thunderstorms taking place above the earth every minute of the day and night, theres enough activity to produce about 100 lightning strikes on earth every second.

　　Parents can use thunder and lightning to help their children learn more about the world around them. When children understand that the light of the lightning flashing reaches their eyes almost at the same moment, but the sound of the thunder takes about 5 seconds to travel just one mile,they can begin to time the interval between the flash and the crash to learn how close they were to the actual spark.

　　4. What is TRUE about lightning according to the passage?

　　A. Only a small number of lightning flashes occur on earth.

　　B. Lightning travels 5 times faster than thunder.

　　C. Lightning flashes usually jump from one cloud to another.

　　D. There are far more lightning strikes occurring on earth than we can imagine.

　　讲解答案：

　　4. A是非题。由文章第三段第一句话可知，大多数闪电一般在石电发生时有，在地面和云之间跳跃。因此C、D是镨的。对于B,或许会受第四段中but the sound of the thunder takes about 5 seconds to travel just one mile的影响，但事实并不相符，因此选A。