The word "malignant" (line, 2 Para. 1 ) probably means ______.
A. contagious
B. chronic
C. virulent
D. injured
查看答案
A．onceB．neverC．sometimeD．over and over
A. once
B. never
C. sometime
D. over and over
British scientists' demonstration implies that ______.
A. single cancer genes are harmless
B. the development of cancer is a complex process
C. a carcinogenic chemical is required for cancer to develop
D. cancer genes can cause cancer only in conjunction with a carcinogen
Compared with wage cost, the non-wage cost differences in EC countries are much more likely to ______.
A. increase dramatically
B. decline sharply
C. fluctuate intermittently
D. disappear gradually
Cells injected with a single cancer gene ______.
A. were unaffected completely under such circumstances
B. only occasionally developed cancer
C. developed tumor but not cancer
D. were changed but did not become malignant
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