[单项选择]The studies on stress in the early 1970's led to ______


A. widespread concern over its harmful effects
B. great panic over the mental disorder it could cause
C. an intensive research into stress-related illnesses

[单项选择]The studies on stress in the early 1970s led to______.


A. popular avoidance of stressful jobs
B. great fear over the mental disorder
C. a careful research into stress related illnesses
D. widespread worry about its harmful effects

[单项选择]Several international events in the early 1990s seem likely to______, or at least weaken, the trends that emerged in the 1980s.


A. retrieve
B. revolve
C. reverse
D. revive

[单项选择]The stress man's job is to______.


A. test how safe the plane is
B. calculate how strong each part must be
C. work out what height the plane may fly at
D. control the amount of luggage each passenger may carry

[单项选择]

Passage One
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 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 lung, colon(结肠) and breast.
Yunis and other investigators have found that petroleum-based products--notabl
A. Scientific Findings.
B. Cancer-causing Genes.
C. Chromosome.
D. How Cancer Is Forme