lecture 2，讲Astronomy的，倒数第二题，according to the professor, why do radio astronomers sometimes have difficulty studying very distant objects?选两个，答案里有个radio waves from space are rest very strong,但是听力里说了One problem is that radio waves from these far away objects, even though they can get through, are extremely faint. 难道是答案错了？但是选什么还是搞不懂。谢谢了！！
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发表于 2012-3-2 14:21:03
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