单项选择题

How many kinds of radiation are feared by astronauts

A．Two.
B．Three.
C．Four.
D．None.
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When will showers reach south-west England and the southern coast of Wales
单项选择题
In the author’s opinion, why do we search the stars or moon
A．We have to know something about them.
B．We must realize space tour.
C．We can’t help ourselves.
D．We make up our minds to do that.
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