GRE模拟题：自测试题二（4）
文章作者 100test 发表时间 2007:02:25 20:09:24
来源 100Test.Com百考试题网
11.The early universe contained only the lightest
elements， hydrogen and helium. Heavier elements，
such as carbon， form only in nuclear reactions in
stars and are dispersed when the stars explode. A
recently discovered gas cloud contained carbon
several billion years ago， when the universe was
no more than two billion years old.
If the statements above are true， which of the
following must， on the basis of them， also be true？
（A）The earliest stars contained only hydrogen.
（B）Some stars were formed before the universe was
two billion years old.
（C）The carbon in the gas cloud later formed part of
some stars.
（D）No stars identified to date are as old as the gas
cloud.
（E）The gas cloud also contained hydrogen and
helium.
12.Sleep deprivation is a
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