四级练习2013.09.06
[audio]http://sound.yywz123.com/tingbbs/cet4/cet420130906.mp3[/audio]After studying the X-rays from the object, Patnaude says there's no direct evidence that the supernova 1979C (1)_____________________________. The X-ray signature detected by NASA's orbiting Chandra telescope provides only indirect evidence. But his colleague Avi Loeb says that if it is a black hole, it could provide important evidence of the energy sources that power a supernova. It also provides an opportunity (2)_____________________________that exist in the universe:
"Very high densities, close to that of an atomic nucleus. And we cannot really reproduce these conditions in the laboratory. And so by observing the sky, we're able to learn about environments ... that can only be observed out there, in the universe." Loeb and Patnaude will be publishing their (3)_____________________________.
**** Hidden Message ***** Good eno
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