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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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.
单项选择题
You can use several ways to communicate with others except ______.
A．using language
B．making eye contact
C．by the posture
D．using ear contact
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