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我这次确实是遇到高分题库了。貌似第二篇阅读就遇到传说中的暗物质那篇。
这篇文章其实不难,和prep里那个macho部分内容重叠。 第一段是介绍暗物质这个东西,说银河里大部分物质都是暗物质什么什么的 第二段介绍那个macho,怎么去找macho。和prep里的很像。 第三段介绍说 科学家用第二段的方法找暗物质,成效不显著,不敢对暗物质下定论。还说科学家原来预计银河系外围有好多暗物质,但是后来发现在银河中央发现的暗物质比外围多。
题目全忘了。
附prep原文 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.
CR里的两道题,一道是渔网gill那个,机经里的答案不对。(其实我当时看机经就感觉到答案不对,没有get point)正确似乎是“在其他地区,用了gill以后捕鱼的人比以前少了”
还有是一个instinct的。说人们在潜意识里累计经验,熟练的人最后凭feeling就能把事做好,不需要复杂的决策树。然后说熟练的卡车司机仅凭听觉等感官就能发现这车哪里坏了。让draw a conclusion。一个选项似乎是卡车司机修车是凭的感觉。另一个似乎是卡车司机修车不需要有意识地做judgement。我选的前者。
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