[单项选择]

Since the early 1980s, scientists have revealed some 40 human genes involved in cancer. These genes are essential for normal growth, but can be subverted to cause a tumor.
Dr. Jorge Yunis of the University of Minnesota Medical School in Minneapolis has found that 70 percent of oncogenes, or cancer-causing genes, are located near inherited weak points on chromosomes(染色体). Varying from individual to individual, vulnerable to chemical carcinogens(致癌剂) ,X rays and other cancer-inducing agents.
"If a chromosome snaps apart in the immediate vicinity of an oncogene," says Yunis, "normal genetic control mechanisms could break down and the stage would be set for the formation of cancer." Younis hag shown that such a sequence occurs at the beginning of numerous leukemias (白血病), lymphomas (淋巴瘤) and some tumors of the lung, colon (结肠) and breast.
Yunis and Other investigators have found that petroleum-based products--notably pesticides and insectic
A. The lung.
B. The colon.
C. The chromosomes.
D. The breast.

[单项选择]Since the early 1980s, scientists have revealed some 40 human genes involved in cancer. These genes are essential for normal growth, but can be subverted to cause a tumor.
Dr. Jorge Yunis of the University of Minnesota Medical School in Minneapolis has found that 70 percent of oncogenes, or cancer-causing genes, are located near inherited weak points on chromosomes(染色体). Varying from individual to individual, vulnerable to chemical carcinogens(致癌剂) ,X rays and other cancer-inducing agents.
"If a chromosome snaps apart in the immediate vicinity of an oncogene," says Yunis, "normal genetic control mechanisms could break down and the stage would be set for the formation of cancer." Younis hag shown that such a sequence occurs at the beginning of numerous leukemias (白血病), lymphomas (淋巴瘤) and some tumors of the lung, colon (结肠) and breast.
Yunis and Other investigators have found that petroleum-based products--notably pesticides and insecticides--damage specific sites on at l
A. harmful to the human body
B. necessary to the human body
C. the elements that form cancer
D. useless to the human body

[填空题]computer of the early 1980s. Government statisticians cannot properly correct

[单项选择]

Since the early eighties we have been only too aware of the devastating effects of large-scale environmental pollution. Such pollution is generally the result of poor government planning in many developing nations or the short-sighted, selfish policies of the already industrialized countries which encourage a minority of the world’s population to squander the majority of its natural resources.
While events such as the deforestation of the Amazon jungle or the nuclear disaster in Chernobyl continue to receive high...remembered that not all pollution is on this grand scale. A large proportion of the world’s pollution has its source much close to home.
Avoiding pollution can be a fulltime job. Try not to inhale traffic fumes, keep away from chemical plants and building-sites; wear a mask when cycling. It is enough to make you want to stay at home. But that, according to a growing body of scientific evidence, would also be a bad idea. Research shows that l
A. has increased since the eighties
B. is at its worst in industrialized countries
C. results from poor relation between nations
D. is caused by human self-interest

[单项选择]Young people in the early 1980s are taking on a set of attitudes and values remarkably different from those of the stormy’ 60s and ’70s. Instead of anti-establishment outbursts, today’s younger generation had turned more thoughtful and more serious. There is heightened concern for the future of the country and a yearning for the traditions and support systems that gave comfort in the past. Many young men and Women of high-school and college age are having second thoughts about the "new morality" and condemn what a soaring divorce rate has done to families. They speak openly of gaining strength from religion. Patriotism, too, seems to be making a modest comeback.
One change in the early 1980s is a questioning of the permissive moral climate of recent years. More young people, while hesitant to preach or to condemn their peers, cite the destructive effects of the drugs and alocohol that are so widely available in the schools. It is peer pressure that pushes teenagers into drugs, but
A. Young People in the U.S.—A Turn Back to Traditional Values
B. Youth on the Move
C. American Moral Values
D. Today’s American Young People