39. Quasars---celestial objects so far away that their light takes at least 500 million years to reach Earth---have been seen since 1963. For anything that far away to appear from Earth the way quasars do, it would have to burn steadily at a rate that produces more light than 90 billion suns would produce. But nothing that burns at a rate that produces that much light could exist for more than about 100 million years.
If the statements above are true, which one of the following must also be true on the basis of them?
(A) Instruments in use before 1963 were not sensitive enough to permit quasars to be seen.
(B) Light from quasars first began reaching Earth in 1963.
(C) Anything that from Earth appears as bright as a quasar does must produce more light than would be produced by 90 billion suns.
(D) Nothing that is as far from Earth as quasars are can continue to exist for more than about 100 million years.
(E) No quasar that has ever been seen from Earth exists any longer.
答案是E,它是指比什么长(exists any longer than what?),死活想不通,C不对吗?作者: mingmings 时间: 2013-6-14 18:33
The question is asking you a Conclusion based on the statement provided. Any copy of the original sentence could never be the conclusion/answer. The answer "cannot be a restatement of a sentence" (Princeton Review on GMAT 2003). Therefore, C is inproper.
Other tips by Princeton:
Support all evidences in the passage, not just part of all premises.
Out of scope choices are wrong.
Also, a conclusion is what the auther attemping to draw following the statement. You need to fill the last gap.
However, make sure you don't confuse the Conclusion questions with Infer questions.作者: hgjtytryr 时间: 2013-6-18 20:17
我觉得C也没有错啊
那些和quasars一样的亮的星星要产生90 billion太阳的光亮
这不是重复了题目第二句 ...
songxueer 发表于 2013-6-16 08:24
别忘了第二句还有个条件"For anything that far away to appear from Earth the way quasars do" 就是说要和quasars一样远!
(D) Nothing (that can be seen from Earth)that is as far from Earth as quasars are can continue to exist for more than about 100 million years.作者: headhunter 时间: 2013-6-20 06:03