9.In earliest times,men considered lightning to be one of the great mysteries of nature.
Some ancient people believed that lightning and thunder were the weapons of the gods.
In reality,lightning is a flow of electricity formed high above the earth.A single flash of lightning 1.6kilometres long has enough electricity to light one million light bulbs (灯泡).
The American scientist and statesman,Benjamin Franklin,was the first to show the connection between electricity and lightning in 1752.In the same year he also built the first lightning rod (避雷针).This device protects buildings from being damaged by lightning.
Modern science has discovered that one stroke of lightning has a voltage (电压) o more than 15million volts (伏特).A flash of lightning between a cloud and the earth may be as long as 13kilometers,and travel at a speed of 30million meters per second.
Scientists judge that there are about 2,000million flashes of lightning per year.Lightning hits the Empire State Building in New York City 30to 48times a year.In the United States alone it kills an average of one person every day.
The safest place to be in case of an electrical storm is in a closed car.Outside,one should go to low ground and not get under trees.Also,one should stay out of water and away from metal fences.Inside a house,people should avoid open doorways and windows and not touch wires or metal things.
With lightning,it is better to be safe than sorry?
9.People once thought lightning came fromB.
A.the sky
B.the gods
C.the earth
D.nature
10.Lightning can travelD.
A.as quickly as water
B.not so quickly as electricity
C.at very low speed
D.at very high speed
11.Which of the following is NOT true?C
A.In the U.S about one person per day dies from lightning.
B.The Empire State Building frequently gets hit by lightning.
C.Swimming during a thunder storm is a good idea.
D.A closed car is the best place to be during an electrical storm.
12.According to the passage what do you think all buildings need?C
A.Metal fences.
B.Electricity.
C.lightning rods.
D.Machines.
分析 文章大意:本文主要介绍了闪电的有关知识.
解答 9.B 细节题.由第一段Some ancient people believed that lightning and thunder were the weapons of the gods.一些古代的人认为雷声和闪电是诸神的武器.故选B.
10.D 细节题.第四段A flash of lightning between a cloud and the earth may be as long as 13 kilometers,and travel at a speed of 30 million meters per second.闪电能够以每秒3000万米的速度传播.可知,它的速度相当快.故选D
11.C 细节题.第六段one should stay out of water and away from metal fences.在雷雨交加的天气,人们也应该远离水和金属物.因此,在雷雨天气中,游泳时一个好主意是错误的.故选C.
12.C 细节题.第三段In the same year he also built the first lightning rod (避雷针).This device protects buildings from being damaged by lightning.美国科学家发明了避雷针,这种装置能够保护建筑物不被闪电损坏,因此,所有的建筑都需要避雷针.故选C
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