单项选择题
A．exposure to even tiny amounts of radiation is fatal B．the effect of exposure to radiation is slow in coming C．radiation is avoidable in space exploration D．astronauts in spacesuits needn’t worry about radiation damage
21（）A．under the thumbB．below the handsC．subject to the ...
单项选择题21（）
A．under the thumb B．below the hands C．subject to the palm D．in the fingers
According to the passage, what was the percentage of Am...
单项选择题According to the passage, what was the percentage of American adults doing regular physical exercises two years ago（）
A．About 70%. B．Nearly 60%. C．Almost 50%. D．More than 12%.
The passage seems to be from （）A．a review of a filmB．a ...
单项选择题The passage seems to be from （）
A．a review of a film B．a book about the U. S. Air Force C．an essay on satire D．a review of a book
