Newspapers often tell us of floods in some parts of the United States.　　Although given less publicity, the agricultural damage done by the many smaller, more frequent floods usually far exceeds the losses caused by the very grand ones. In the Central States, ditches and drains cause the flows from spring rains and melting snow to run far more rapidly than in the days before white men settled on the land. Once, excess spring flood waters emptied into lakes and swampy lands, there to be detained for slow release into stream and rivers. Now, systematic drainage has actually eliminated these natural reservoirs.　　The effects of eliminating the natural forest cover are shown in the gullied farm lands and widened stream channels found in some densely settled areas. Partly because the stream channels are more or less filled with material washed down from the uplands, and partly because storm runoff has increased, the channels are today no longer able to carry all the flow from heavy rains. This explains why the streams overtop banks far more often than in the days before settlement.　　A. River Rising! River Rising!　　C. Flooding in the U. S.　　32. All of the following cause floods EXCEPT______.　　B. melting snow　　D. porous soil　　A. lakes and swamps once acted like natural reservoirs　　C. stream channels are the best carriers of water　　34. According to the selection, streams overtop their banks partly because______.　　B. ditches and drains lead into them　　D. snow melts more rapidly nowadays　　A. cause no damage　　C. cause less agricultural damage than the many smaller, more frequent floods　　Mobile Phone and Diseases　　But Darius Leszczynski, who headed the 2-year study and will present findings next week at a conference in Quebec, said more research was needed to determine the seriousness of the changes and their impact on the brain or the body.　　We know that there is some biological response. We can detect it with our very sensitive approaches, but we do not know whether it can have any physiological effects on the human brain or human body, Leszczynski said.　　The study focused on changes in cells that line blood vessels and on whether such changes could weaken the functioning of the blood-brain barrier, which prevents potentially harmful substances from entering the brain from the bloodstream, Leszczynski said.　　Increased protein activity might cause cells to shrinknot the blood vessels but the cells themselvesand then tiny gaps could appear between those cells through which some molecules could pass. he said.　　These are not life-threatening problems but can cause a lot of discomfort, he said, adding that a Swedish group had also suggested a possible link with Alzheimers disease.　　Leszczynski said that he, his wife and children use mobile phones, and he said that he did not think his study suggested any need for new restrictions on mobile phone use.　　A　Mobile phone radiation can increase protein activities and such activities can make the protective shield more permeable.　　C　Mobile phone radiation will bring stress to people exposed to it.　　37　Whats the result of the French study? _________　　B　Mobile phone may affect ones normal way of thinking.　　D　A protein called hsp27 is killed by mobile phone radiation.　　A　Fatigue.　　C　Alzheimers disease.　　39　According to the passage, what would be the future of the use of mobile phone? _________　　B　People dare not use mobile phone because of its radiation.　　D　There will be new restrictions on the use of mobile phone.　　A　The research in Finland found that mobile phone radiation will affect ones brain.　　C　Increased protein activity might cause cells to shrink.　　Electronic Mail　　Electronic networks, woven into the fabric of scientific communication these days, are the route to colleagues in distant countries, shared data, bulletin boards and electronic journals. Anyone with a personal computer, a modem and the software to link computers over telephone lines can sign on. An estimated five million scientists have done so with more joining every day, most of them communicating through a bundle of interconnected domestic and foreign routes known collectively as the Internet, or net.　　Jeremy Bernstei, the physicist and science writer, once called E-mail the physicists umbilical cord. Lately other people, too, have been discovering its connective virtues. Physicists are using it; college students are using it, everybody is using it, and as a sign that it has come of age, the New Yorker has celebrated its liberating presence with a cartoon-an appreciative dog seated at a keyboard, saying happily, On the Internet, nobody knows youre a dog.　　A　direct and reliable　　C　money-saving　　42　How is the Internet or net explained in the passage? __________　　B　Electronic routes used to fax or correspond overnight.　　D　Electronic routes connected among millions of users, home and abroad.　　A　The quick speed of correspondence may have ill-effects on discoveries.　　C　It quickens mutual communication even if it does not accelerate discoveries.　　44　What does the sentence On the Internet, nobody knows youre a dog.imply in the last paragraph? __________　　B　E-mail has become very popular.　　D　E-mail deprives dogs of their owners love.　　A　Their functions cannot be replaced by E-mail.　　C　Less and less people will use them.　　31. C 3 2. D 3 3. A 3 4. A 35. C　　41 A 42 D 43 C 44 B 45 C

　　Newspapers often tell us of floods in some parts of the United States.　　Although given less publicity, the agricultural damage done by the many smaller, more frequent floods usually far exceeds the losses caused by the very grand ones. In the Central States, ditches and drains cause the flows from spring rains and melting snow to run far more rapidly than in the days before white men settled on the land. Once, excess spring flood waters emptied into lakes and swampy lands, there to be detained for slow release into stream and rivers. Now, systematic drainage has actually eliminated these natural reservoirs.　　The effects of eliminating the natural forest cover are shown in the gullied farm lands and widened stream channels found in some densely settled areas. Partly because the stream channels are more or less filled with material washed down from the uplands, and partly because storm runoff has increased, the channels are today no longer able to carry all the flow from heavy rains. This explains why the streams overtop banks far more often than in the days before settlement.　　A. River Rising! River Rising!　　C. Flooding in the U. S.　　32. All of the following cause floods EXCEPT______.　　B. melting snow　　D. porous soil　　A. lakes and swamps once acted like natural reservoirs　　C. stream channels are the best carriers of water　　34. According to the selection, streams overtop their banks partly because______.　　B. ditches and drains lead into them　　D. snow melts more rapidly nowadays　　A. cause no damage　　C. cause less agricultural damage than the many smaller, more frequent floods　　Mobile Phone and Diseases　　But Darius Leszczynski, who headed the 2-year study and will present findings next week at a conference in Quebec, said more research was needed to determine the seriousness of the changes and their impact on the brain or the body.　　We know that there is some biological response. We can detect it with our very sensitive approaches, but we do not know whether it can have any physiological effects on the human brain or human body, Leszczynski said.　　The study focused on changes in cells that line blood vessels and on whether such changes could weaken the functioning of the blood-brain barrier, which prevents potentially harmful substances from entering the brain from the bloodstream, Leszczynski said.　　Increased protein activity might cause cells to shrinknot the blood vessels but the cells themselvesand then tiny gaps could appear between those cells through which some molecules could pass. he said.　　These are not life-threatening problems but can cause a lot of discomfort, he said, adding that a Swedish group had also suggested a possible link with Alzheimers disease.　　Leszczynski said that he, his wife and children use mobile phones, and he said that he did not think his study suggested any need for new restrictions on mobile phone use.　　A　Mobile phone radiation can increase protein activities and such activities can make the protective shield more permeable.　　C　Mobile phone radiation will bring stress to people exposed to it.　　37　Whats the result of the French study? _________　　B　Mobile phone may affect ones normal way of thinking.　　D　A protein called hsp27 is killed by mobile phone radiation.　　A　Fatigue.　　C　Alzheimers disease.　　39　According to the passage, what would be the future of the use of mobile phone? _________　　B　People dare not use mobile phone because of its radiation.　　D　There will be new restrictions on the use of mobile phone.　　A　The research in Finland found that mobile phone radiation will affect ones brain.　　C　Increased protein activity might cause cells to shrink.　　Electronic Mail　　Electronic networks, woven into the fabric of scientific communication these days, are the route to colleagues in distant countries, shared data, bulletin boards and electronic journals. Anyone with a personal computer, a modem and the software to link computers over telephone lines can sign on. An estimated five million scientists have done so with more joining every day, most of them communicating through a bundle of interconnected domestic and foreign routes known collectively as the Internet, or net.　　Jeremy Bernstei, the physicist and science writer, once called E-mail the physicists umbilical cord. Lately other people, too, have been discovering its connective virtues. Physicists are using it; college students are using it, everybody is using it, and as a sign that it has come of age, the New Yorker has celebrated its liberating presence with a cartoon-an appreciative dog seated at a keyboard, saying happily, On the Internet, nobody knows youre a dog.　　A　direct and reliable　　C　money-saving　　42　How is the Internet or net explained in the passage? __________　　B　Electronic routes used to fax or correspond overnight.　　D　Electronic routes connected among millions of users, home and abroad.　　A　The quick speed of correspondence may have ill-effects on discoveries.　　C　It quickens mutual communication even if it does not accelerate discoveries.　　44　What does the sentence On the Internet, nobody knows youre a dog.imply in the last paragraph? __________　　B　E-mail has become very popular.　　D　E-mail deprives dogs of their owners love.　　A　Their functions cannot be replaced by E-mail.　　C　Less and less people will use them.　　31. C 3 2. D 3 3. A 3 4. A 35. C　　41 A 42 D 43 C 44 B 45 C