题目内容
In St. Louis, Missouri, 9,000 people were forced to leave their homes while the city was in danger. St. Louis is just downriver from the points where the Missouri and Illinois Rivers flow into the Mississippi. All three rivers were flooding. But the city escaped the worst when levees (堤) broke upriver. A levee is built of river sand and clay (粘土).
Eleven miles of flood walls were built in the late 1960’s. The walls are 18 inches thick and 5 to 22 feet high. They were designed to protect against a 52-foot flood. In St. Louis, water almost reached the top of flood walls. It measured 49.4 feet.
第41题：The flood referred to in the passage ________.
[A] was the heaviest one in the history
[B] happened in Missouri and Illinois states
[C] happened in less than twenty percent of the states of U.S.A.
[D] was recorded several times
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听第8段材料，回答11~13题。
第11题：
Paragraph 2_____________
根据短文回答 36～40 题。Effects of Environmental Pollution
If pollution continues to increase at the present rate。formation of aerosols(浮质)in the atmosphere will cause the onset(开始)of an ice age in about fifty years' time.This conclusion.reached by Dr S.I.Rasool and Dr S.H.Schneider of the United States Goddard Space Flight Centre,answers the apparently conflicting questions of whether an increase In the carbon dioxide(二氧化碳)content of the atmosphere will cause the Earth to warm up or increasing the aerosol content will cause it to cool down.The Americans have shown conclusively that the aerosol question is dominant.
Two specters haunting conservationists have been the prospect that environmental pollution might lead to the planet's becoming unbearably hot or cold.One of these ghosts has now been laid,because it seems that even an increase in the amount of carbon dioxide in the atmosphere to eight times its present value will produce an increase in temperature of only 2℃,which would take place over several thousand years.But the other problem now looms(隐约出现)larger than ever.
Aerosols are collections of small Liquid or solid particles dispersed in air or some other medium.The particles are all so tiny that each is composed of only a few hundred atoms.Because of this they can float in the air for a very long time.Perhaps the most commonly experienced aerosol is industrial smog(烟雾)of the kind that plagued London in the 1 950s and is an even greater problem in Los Angeles today.These collections of aerosols reflect the Sun's heat and thereby cause the Earth to COOL. Dr Rasool and Dr Schneider have calculated the exact effect of a dust aerosol layer just above the Earth's surface in the temperature of the planet.As the layer builds up,the present delicate balance between the amount of heat absorbed from the Sun and the amount radiated from the Earth is disturbed.The aerosol Ayer not only reflects much of the Sun's light but also transmits the infrared(红外线的)radiation from below.S0,while the heat input to the surface drops,the loss of heat remains high until the planet cools to a new balanced state.
Within fifty years,if no steps are taken to stop the spread of aerosols in the atmosphere,a cooling of the Earth by as much as 3.5℃seems inevitable.If that lasts for only a few years it would start another ice age,and because the growing ice caps at each pole would themselves reflect much of the Sun's radiation it would probably continue to develop even if the aerosol layer were destroyed.
The only bright spot in this gloomy forecast lies in the hope expressed by Dr Rasool and Dr Schneider that nuclear power may replace fossil fuels in time to prevent the aerosol content of the atmosphere from becoming critical.
第6题：The author\'s main purpose in writing the article is to warn of（）.
A warm weather.
B hot weather.
C a new ice age.
D a newiceberg.
B“As I stood in front of the grave (墓) of President Richard Nixon, I was thinking about the time 25 years ago when this president helped bring the United States and China closer together. Young people of our two countries should help this relationship grow.”
This remark was made by a Shanghai student when speaking to his fellow students at the Nixon Library in California, U.S.A. He was one of 80 middle school students from China attending a month-long “Youth Summit”. The Summit was to mark the 25th anniversary (周年) of President Nixon’s journey to China, which was the turning point in China-US relations.
The Youth Summit was aimed at increasing understanding and friendship between young students of the two countries through visits and discussions. Seventy-five American students were selected to visit China. They also visited the Nixon Library on July 21 before leaving for Beijing the next day. The head of the Library said he was pleased to see the American and Chinese students talking and laughing together.
One Chinese student said, “I didn’t find it particularly difficult to talk with Americans. We have our differences, but we have a lot in common. Dialogue is good for us.”
第40题：The works “Youth Summit” refer to ________.
[A] visits to the Nixon Library
[B] the Chinese students’ visit to the U. S.
[C] a meeting discussing relations between China and the U. S.
[D] activities to strengthen the ties between the Chinese and American students
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