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四、阅读理解
36、根据以下材料回答第 1～4 题：
Passage One
Since the early l980s，scientists have revealed some 40 human genes involved in caneer．These genes are essential for normal growth，but can be subverted to cause a tumor．
Dr．Jorge Yunfs of the University of Minnesota Medical School in Minneapolis hasfound that 70 percent of oncogenes，or cancer-causing genes，are located near inheritedweak points on chromosomes(染色体)．Varying from individual to individual，vulnerableto chemical carcinogens(致癌剂)，X rays and other cancer_inducing agents．
“If a chromosome snaps apart in the immediate vicintiy of an oncogene，”says Yunis，“normal genetic control mechanisms could break down and the stage would be set for the formation of cancer．”Younis has shown that such a sequence OCCURS at the beginning of numerous leukemias(白血病)，lymphomas(淋巴瘤)and some tumors of the lun9，coIon(结肠)and breast．
Yunl‘s and other inverstigators have found that petroleum-based products-notably Desticides and insecticidesdamage specific sites on at least two of the 23 pairs of human chromosomes that carry genetic information．Similarly，tobacco smoke tends to attack a part of another ehromosome．
From paragraph I，we know that some 40 genes involving in cancer are ．



37、Where are most likely to be affected by caner－inducing agents according to the passage?


38、According to the context，the word in“oncogenes”in para,2 means ．


39、Under what conditions will the formation of cancer begin?


40、根据以下材料回答第 1～4 题：
Passage Two
A greenhouse is a building made of glass，which is used for keeping plants warm when the outside temperature is low．In a similar way there are several gases in t he atmosphere which trap(捕捉)the heat produced by the sun and prevent it from escapin9．This is called the“greenhouse effect”and these gases are known as“greenhouse gases”．This is not simply air pollution，because without them the earth would be 30 degrees colder and human life would not exist．In other words，the“greenhouse effect”is a natural course which is to some degree helpful to us．
The Droblem is that we have been putting too many of these gases into the earth’satmosDhere by burning large quantities of coal and oil and by cutting down forests．The rapid increase in greenhouse gases is making the world warmer，the world’s temperature has already gone up by half a degree this century，and the sea level has risen by lo centime ters．If carbon dioxide(二氧化碳)in the atmosphere doubles，there will probably be a rise in the earth temrmrature of between land 4．It seems ca small increase，but it would be enough to causemajor changes in geography and agriculture．Large areas of the world would be flooded， and some areas would become dry and unable to produce crops．SO，it’s important for human beings to realize greenhouse effect and pay enough attention to it．
What is“green house used”for?



41、If there were no greenhouse effect， ．


42、Which of the following is not true?


43、Suppose the earth’S temperature rose’by 3 degrees， ．


44、根据以下材料回答第 1～4 题：
Passage Three
Three women who secretly buried an 80-year-old woman were put into prison at Birmingham yesterday．Two of them，including the dead woman’S daughter，kept on collecting her pension(退休金)after her death until their secret was made known to others twp years later．The court(法庭)heard that one of the women put on“an Oscar(奥斯卡金奖)winning perfomance"by pretending to be the old worflan asleep in bed when a social worker called five months after Mrs．Townsend’s death．
Mrs．Townsend’s death had been covered up and it was discovered ．




45、Of the three women that buried Mrs．Townsend secretly，one was ．