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考古君来啦~~~上月考完~~本月帮大家考考古！！~~大家加油！！纯属自己激动考古~~现在有给力木寻云大大一起考~~逻辑考古目前有3只野狗待好心人领走啊~~~http://forum.chasedream.com/GMAT_Math/thread-772850-1-1.html 走过路过不要错过~~
现在只把未确认的狗粘上来，不然太多了~~方 便狗主领狗~~大家帮顶，让狗主看到~~~大家帮着顶一顶~~欢迎狗主领狗~~我把已确认的狗放在word里面，大家下载最下面最新的哈~ 感谢各位确认狗狗的同学，我自己还要准备考托福，木有感谢到的请见谅~~~ 感谢treefrog提供蜂蜜相关背景资料：
http://www.honeybeesuite.com/the-color-of-honey/
感谢redredfox提供太阳起源相关资料
http://www.astrobio.net/amee/spring_2007/features_07.htm 10.10 南亚经济 . 乌鸦10.11 美国规模经济，蜂蜜， 植物AP授粉（谢谢lxlxl）太阳起源 ，经理人与股东， 铁和全球变暖 两种广告比较---已确认
暗物质 MACHO ~~ --待确认
【MACHO暗物质 】
【V1】一段是说科学家们认为MACHO是一个很长的名词的简写，大概就是给black matter的质量还是什么，然后说认为visible的只占universe质量的5%，剩下的至少90%都是blackmatter。只要是理论
第二段是说科学家是怎么印证blackmatter存在那，做的实验是说如果宇航员观测宇宙中的一个星体还是什么，如果black matter从宇航员和星体中间穿过，由于blackmatter质量大，会使光产生弯曲，弯向质量大的blackmatter，这样宇航员就只能看到brightening。。证明有black matter的存在。
第三段是说后来通过observation发现black matter不是even sperse的，是center of our galaxy比较dense的。然后又说还需要进一步的确认才能得出结论，说还是可能有问题的这个研究。
【V2】(770)
总共三段，由于考前对这篇大概的内容已经非常非常熟悉了。所以考试扫了一眼不到40s就把文章大概结构内容看了一遍。
这篇主要就是，介绍一种宇宙中暗物质MACHO,然后介绍观察这种暗物质的方法。
第一段：说是宇宙中的大部分物质并不是像人们想象的那样由可见的一些物质构成。宇宙质量的95%是由invisible 物质构成，剩下的5%才由visible物质构成。不可见的物质中astronomer（是天文学家的意思）发现了一种新的物质，叫做MACHO （massive compact halo objects）。这些物质起初被认为主要存在于outspace。（这里应该说的是银河系以外的space，out space 这个词记得很清楚是有的）
第二段：讲以前astronomer天文学家常常会用一种叫什么gas XX的方法去探究这些暗物质的存在及有多少。后来发现这种方法有很大的局限性，然后说是局限在哪儿（这里就不记得具体怎么说的，只记得这里有就一句话）。Astronomer 最近起用了一种新的方法，叫做microlening（微透镜，考前楼主好好了解了一些这个，大家可以去谷歌一下）。然后说了下microlening方法的原理（就是jj里重要文献里的几句话）The gravity of a MACHO that had so drifted, astronomers agree, wouldcause the star's light rays, which would otherwise diverge, to bend together sothat, as observed from Earth, the star would temporarily appear to brighten, aprocess known as microlensing. 所以天文学家就可以通过观察start’slight rays 的弯曲与亮度来探究MACHO的分布。
第三段天文学家最开始用gasXX方法，认为MACHO在银河系以外的out space 分布较多。然而好像与实际情况有些不一样。所以现在天文学家又用micorlening方法判断预测。MACHO在银河系的center分布较集中。（这里又有个小转折）但是天文学家在没有更确定的证据sufficient evidence之前，也不敢就很确定实际分布就是如此。但有一点天文学家是可以确定的是，银河系MACHO的分布比以前估计的要多得多。
Q1：主题题
选的是describe a object 什么什么的，then introduce methodsto detect 什么什么的。
Q2：天文学家在此之前unexpectedabout MACHO that…?
选银河系center 的MACHO 比较多。
Q3: 高亮“sufficientevidence “ 然后infer 什么?
我最终还是选了，jj上提到的那个答案，micorlening 已经是目前最准确的测量方法了。其它几个答案感觉也不对。就这个答案较prefer了。
Q4：好像还有一题问，关于原文，下面那个说法是正确的。
有一个选项说，在观测MACHO时，现在天文学家两种方法都在同时结合运用。这个选项应该是错的，因为原文只是提到第一个方法有局限，然后现在在用一种新的方法。没有提到说两种方法结合起来用。
有狗主说意思PREP原题~待确认~~！
Inthe 1980's, astronomer Bohdan Paczynski proposed a way of determining whetherthe enormous dark halo constituting the outermost part of the Milky Way galaxyis composed of MACHO's (massive compact halo objects), which are astronomicalobjects too dim to be visible.  aczynskireasoned that if MACHO's make up this halo, a MACHO would occasionally drift infront of a star in the Large Magellanic Cloud, a bright galaxy near the MilkyWay. The gravity of a MACHO that had sodrifted, astronomers agree, would cause the star's light rays, which wouldotherwise diverge, to bend together so that, as observed from Earth, the starwould temporarily appear to brighten, a process known as microlensing. Because many individual stars are ofintrinsically variable brightness, some astronomers have contended that thebrightening of intrinsically variable stars can be mistaken for microlensing. However, whereas the different colors oflight emitted by an intrinsically variable star are affected differently whenthe star brightens, all of a star's colors are equally affected bymicrolensing. Thus, if a MACHO magnifiesa star's red light tenfold, it will do the same to the star's blue light andyellow light. Moreover, it is highlyunlikely that a star in the Large Magellanic Cloud will undergo microlensingmore than once, because the chance that a second MACHO would pass in front of exactlythe same star is minuscule.
Q31. P2-rc Question#55. 639-01 (23881-!-item-!-188;#058&000639-01)
Itcan be inferred from the passage that which of the following would constitutethe strongest evidence of the microlensing of a star in the Large MagellanicCloud?
(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 thebrightening of neighboring stars.
(C)The red light of such a star is observed to be brighter than its yellow lightand its blue light.
(D)The red light, yellow light, and blue light of such a star are observed to bemagnified temporarily by the same factor.
(E)The red light of such a star is observed to have increased tenfold.
Q32. P2-rc Question#56. 639-04 (23927-!-item-!-188;#058&000639-04)
Accordingto the passage, Paczynski's theory presumes that if MACHO's constituted theMilky 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 resultthat the star would seem for a time to brighten
(C)become obscured as a result of the microlensing of a star in the LargeMagellanic Cloud
(D)temporarily increase the apparent brightness of a star in the Large MagellanicCloud by increasing the gravity of the star
(E)magnify each color in the spectrum of a star in the Large Magellanic Cloud by adifferent amount
Q33. p2-rc Question#57. 639-06 (23973-!-item-!-188;#058&000639-06)
Thepassage is primarily concerned with
(A)outlining reasons why a particular theory is no longer credited by someastronomers
(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 howinfluential that theory has been
(D)showing how a researcher's theory has been used to settle a dispute between theresearcher and some astronomers
(E)describing a line of reasoning put forth by a researcher and addressing acontention concerning that line of reasoning
加油考古~~~~！
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发表于 2012-10-10 13:22:44
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