og12-116&118

mindysu

我身为理工科的学生为啥觉得这篇宇宙的文章严重违反了我的认知。这篇总是让我很崩溃啊啊啊
想撕书啊啊啊
116 the author`s study indicates that, in comparison with the outermost regions of a typical spiral galaxy, the region just outside the nucleus can be characterized as having
A.  higher rotational velocity and higher luminosity
B.  lower rotational velocity and higher luminosity
C.  lower rotational velocity and lower luminosity
D. similar rotational velocity and higher luminosity
E.  similar rotational velocity and similar luminosity

原文不是说“the rotational velocity in spiral galaxies either remains constant with increasing distance from the center or increases slightly.”那不是b, d都对？

118.   It can be inferred from information presented in the passage that if the density of the universe were equivalent to signi?cantly less than three hydrogen atoms per cubic meter, which of the following would be true as a consequence?
(A)   Luminosity would be a true indicator of mass.
(B)   Different regions in spiral galaxies would rotate at the same velocity.
(C)   The universe would continue to expand inde?nitely.
(D)   The density of the invisible matter in the universe would have to be more than 70 times the density of the luminous matter.
(E)   More of the invisible matter in spiral galaxies would have to be located in their nuclei than in their outer regions.
这题目出的，宇宙膨胀不是应该密度越来越小吗？怎么可能越膨胀密度越大，直到临界呢？

edwardelric

http://forum.chasedream.com/GMAT_RC/thread-442989-1-1.html
这个题目对应的是116
108、
定位到以下原文：
It can be calculated that the critical density of matter needed to brake the expansion and “close” the universe is equivalent to three hydrogen atoms per cubic meter
直接就能推出c
在文章中找答案不要用你的经验去判断

加州女孩

嗯 同意楼上的观点 而且后面不是还有一句：if the expansion of the universe is to stop,there must be enough invisible matter in the universe to exceed the luminous matter in density by a factor of roughly 70.我觉得一丝应该是说只有在宇宙中有足够多的看不见的在密度上超过L的物质，膨胀才会停止。我猜是不是因为质量大 物质间的万有引力大 所以就不能继续膨胀了，请大牛指正