单项选择题

The text seems to imply that other forms of life in the cosmos ______.

A．have never existed
B．have all died out
C．may exist in the future
D．are in existence
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单项选择题
How much does Sagan ,think America should spend on Space Exploration
A．More than she does at present.
B．Less than she does at present.
C．As much as England did in the sixteenth century.
D．All of her gross national income.
单项选择题
Carl Sagan suggests that modem man ______.
A．is very confused about the origin of the Earth
B．might possibly reach life outside the
C．believes it is possible to step off the Earth
D．is historically incapable of exploring the universe
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