In the 1980's, astronomer Bohdan Paczynski proposed a way of determining whether the enormous dark halo constituting the outermost part of the Milky Way galaxy is composed of MACHO's (massive compact halo objects), which are astronomical objects too dim to be visible. Paczynski reasoned that if MACHO's make up this halo, a MACHO would occasionally drift in front of a star in the Large Magellanic Cloud, a bright galaxy near the Milky Way. The gravity of a MACHO that had so drifted, astronomers agree, would cause the star's light rays, which would otherwise diverge, to bend together so that, as observed from Earth, the star would temporarily appear to brighten, a process known as microlensing. Because many individual stars are of intrinsically variable brightness, some astronomers have contended that the brightening of intrinsically variable stars can be mistaken for microlensing. However, whereas the different colors of light emitted by an intrinsically variable star are affected differently when the star brightens, all of a star's colors are equally affected by microlensing. Thus, if a MACHO magnifies a star's red light tenfold, it will do the same to the star's blue light and yellow light. Moreover, it is highly unlikely that a star in the Large Magellanic Cloud will undergo microlensing more than once, because the chance that a second MACHO would pass in front of exactly the same star is minuscule.
文章概况：开头说有一些宇航员提出了一种方法，并用这种方法测试hale中是否包含macho，这种macho肉眼是看不到的。后面就开始不停的论述这个观点，中间的推导过程实在读不懂，反正和light ray和颜色有点关系，这个推导过程一直持续到文章结尾。
23 D
It can be inferred from the passage that which of the following would constitute the strongest evidence of the microlensing of a star in the Large Magellanic Cloud?
(A) The brightness of such a star is observed to vary at irregular intervals.
(B) The brightening of such a star is observed to be of shorter duration than the brightening of neighboring stars.
(C) The red light of such a star is observed to be brighter than its yellow light and its blue light.
(D) The red light, yellow light, and blue light of such a star are observed to be magnified temporarily by the same factor.
(E) The red light of such a star is observed to have increased tenfold.
问的是细节，我们根据 microlensing of a star in the Large Magellanic Cloud?来定位，但是这个破词全篇都是，问题起不到作用了，怎么办？我们来看看选项！这些选项好像都和星星的亮度和光被观测到有关系，如果选项存在一个共同点，那就证明你要读到的原文应该包含这些共同点，我们来看看原文哪句话说得是这些亮度和光被观察，应该是microlensing这个词出现的第一句：the gravity of a MACHO that had so drifted, astronomers agree, would cause the star's light rays, which would otherwise diverge, to bend together so that, as observed from Earth, the star would temporarily appear to brighten, a process known as microlensing. 这句话的大致意思是MACHO重力飘移将会导致曾经分散的光聚集到一起，这样从地球上看起来，这些星就会看起来更亮一些！我们来看看选项
A 说观测是有不规则的间断，没提，杀
B 说亮度持续时间比旁边的星短，说持续时间问题，没提，杀
C 说红光比黄光和蓝光看起来亮，反正说更亮的问题，有点关系，留着
D 说这些光被放大了，也有关系，留着
E 说星的红光增加了tenfold，没提，杀
C和D最大的差距在于C强调的是这些光自己哪个比哪个亮而D强调的是这些光集体被弄亮了，原文说的是这些光一起被聚集到一起了，D更好！
24 B
According to the passage, Paczynski's theory presumes that if MACHO's constituted the Milky Way's dark halo, occasionally a MACHO would
(A) drift so as to lie in a direct line between two stars in the outer Milky Way
(B) affect the light rays of a star in the Large Magellanic Cloud with the result that the star would seem for a time to brighten
(C) become obscured as a result of the microlensing of a star in the Large Magellanic Cloud
(D) temporarily increase the apparent brightness of a star in the Large Magellanic Cloud by increasing the gravity of the star
(E) magnify each color in the spectrum of a star in the Large Magellanic Cloud by a different amount
问如果MACHO包括了milky Way dark halo，MACHO将会怎么样？既然问的是MACHO会怎样，首先想根据MACHO来定位，但是这个词文章太多了，没用，只能根据Milky Way's dark halo来定位，我们可以找到文章第一句话，但是这句话我们刚才已经读过了，说得只是一个现象，没有说如果某个条件存在之后MACHO会产生什么结果？我们继续往后读，后面大概强调的是重力导致光聚集，从地球上观测这些光会更亮一些。我们根据这个内容来看选项。
A 说MACHO会在什么一个位置上，没提，杀
B 说影响光线导致星看起来会更亮一些，沾边，留着
C 变得模糊了，方向反了，杀
D 通过重力增加使得亮度增加，沾边，也留着
E 不同程度地放大了颜色，没提，杀
B和D进行比较，B说MACHO会影响到光从而使得星看起来亮一些，而D强调MACHO通过增加星的重力来增加亮度，文章说得是MACHO重力会影响光聚集，不是MACHO增加了星的重力，与文章所说信息不符合，杀！
25 E
The passage is primarily concerned with
(A) outlining reasons why a particular theory is no longer credited by some astronomers
(B) presenting data collected by a researcher in response to some astronomers' criticism of a particular line of reasoning
(C) explaining why a researcher proposed a particular theory and illustrating how influential that theory has been
(D) showing how a researcher's theory has been used to settle a dispute between the researcher and some astronomers
(A) describing a line of reasoning put forth by a researcher and addressing a contention concerning that line of reasoning
问主旨，我们直接来看选项
A 提出一些原因解释为什么一些宇航员不在信任一个理论，文章一直说宇航员在用这个理论，而这个选项说不再相信，方向不对，杀
B 还说宇航员批评一个东西，方向还是不对，杀
C 说为什么用一个理论并探讨这个理论的影响，有点关系，留
D 说出dispute这个选项方向就于原文不符，杀
E 说为什么用一个理论并列出原文，有点关系，先留着
C和E这两个选项最大的不同在于这两个选项的后办部分，一个强调的是这个理论的影响而另一个强调的是这个理论的原因，文章第二句话开头就说reason that，显然是探讨这个理论应用的原因，选E。
A 提出一些原因解释为什么一些宇航员不在信任一个理论，文章一直说宇航员在用这个理论，而这个选项说不再相信，方向不对，杀
B 还说宇航员批评一个东西，方向还是不对，杀
C 说为什么用一个理论并探讨这个理论的影响，有点关系，留
D 说出dispute这个选项方向就于原文不符，杀
E 说为什么用一个理论并列出原文，有点关系，先留着
C和E这两个选项最大的不同在于这两个选项的后办部分，一个强调的是这个理论的影响而另一个强调的是这个理论的原因，文章第二句话开头就说reason that，显然是探讨这个理论应用的原因，选E。
