单项选择题

The principle discovery in this century shows______.

A．man has overthrown Newton' s laws of physics
B．man has solved a new set of gigantic puzzles
C．man has lost many scientific discoveries
D．man has given up some of the once accepted theories

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热门试题

单项选择题Now scientists have found in the past few years______.

A．the exposure of DNA to the public is unnecessary
B．the tiny cell in DNA is a neat little machine
C．man knows nothing about DNA
D．man has much to learn about DNA

单项选择题Special words used in technical discussion______.

A．never last long
B．should be confined to scientific fields
C．may become part of common speech
D．are considered artificial language speech