[C] it could detect any star and exoplanet surrounding the Earth

[D] it could search out the promising sign for finding extraterrestrial life

3. 无线电望远镜也可以用于搜索外星生物，因为 _____。

[A] 它可以使得天体物理学家非常精细地观察所有的行星

[B] 它可以发现保护生物不受太空颗粒的碰撞攻击的磁场

[C] 它可以探测到地球周围的任何行星和系外行星

[D] 它可以发现寻找外星生物的迹象

答案：B　难度系数：☆☆☆☆

分析：推理题。根据第三段，该装置还可以用来搜索外星生物，是因为它可以探测到行星和系外行星的磁场，有磁场存在就表明可能有生物存在。因此，答案为B。

4. The word “tenuous” (Line 2, Paragraph 5) most probably means _____.

[A] slender

[B] dilute

[C] flimsy

[D] thick

4. tenuous这个词（第五段第二行） 最有可能的意思是 _____。

[A] 微薄的

[B] 稀薄的

[C] 薄的

[D] 厚的

答案：B　难度系数：☆

分析：猜词题。根据常识，月球大气层应该是稀薄的，因此，在四个选项中，B最为符合这个意思，是正确答案。

5. The third and fourth projects are different from earlier ventures dropped on the moon in the following aspects except _____.

[A] the position of the reflectors remains on the lunar surface

[B] more advanced applications will be adopted for research

[C] the scope of reflectors will be expanded on the lunar equator

[D] more surface of the moon will be covered

5. 第三个和第四个计划与早期的探月冒险的不同之处为除 _____ 的以下几点。

[A] 反射器在月球表面的位置是没有变化的

[B] 更加先进的设备将会用于研究

[C] 反射器的范围会在月球赤道上扩展

[D] 月球上面积更大的表面将会被覆盖

答案：A　难度系数：☆☆☆

分析：细节题。第六段中提到了不同之处，最后一句表明，要在月球上更多的地方放置更加复杂的设备，因此选项B和D是正确的。而C也提到了分布范围会扩大。选项A说的是相同点，因此，答案为A。





参考译文


把人送入太空也许能成为半岛bandao（中国）新闻，但是对科学研究却没有多大帮助。因此，当George Bush在2004年要求美国宇航局将重点从科学研究转移到载人重返月球时，很多科学家都倍感失望。现在，美国宇航局在重返月球计划中增加了四项科研项目，总算给大家带来了些许安慰。

这些项目中最激动人心的，是一种可以安装在月球背面的无线电天文望远镜。通过这种望远镜，人们可以了解到从宇宙早期至大规模天体结构（如星云和恒星）形成的时期。安装在月球上的无线电天文望远镜可以探测到那些无法在地球表面检测到的长波，因为这些长波都被地球大气层的最外层吸收了。此外，天体物理学家们使该望远镜远离地球上用于通信的波长较短的无线电波，从而能够史无前例地细致地观察早期的宇宙。

使用这台望远镜也许还可以寻找到外星生物，因为它能够描绘出恒星和太阳系外行星（太阳系之外围绕恒星运动的行星）的磁场图。正是由于地球磁场的保护，地球上的生物才能免受来自太空中的高能粒子的袭击，否则这个星球就会变成一片不毛之地。如果能够检测到某个太阳系外行星也像地球一样被磁场包围，就有希望找到地外生命。

该计划由美国华盛顿特区海军研究实验室的Joseph Lazio领导，目标是造出一个三臂状构成的Y字形天线阵，其中每条臂长500米，含16根天线，用塑料薄膜制成，以便由机器人或宇航员平铺在月球表面。

第二项计划的负责人是美国宇航局戈达德太空飞行中心的Michael Collier，该计划将研究太阳风——太阳喷射出的一束带电粒子流——如何与月球表面稀薄的大气相互作用。这种作用产生的低能X射线可以在月球表面被探测到。

第三项和第四项计划彼此相似，并与20世纪60年代末和70年代进行的阿波罗计划和苏联的登月计划也大同小异。现在，那些放置于月球表面的反射器已差不多工作了35年，且仍然为那些对地球物理学和测地学（如研究月球引力场如何随时间而变化）感兴趣的科学家们使用着。大多数反射器都安装在靠近月球赤道的地方。这两项计划的主管人是同属美国宇航局戈达德太空飞行中心的Stephen Merkowitz以及马里兰大学的Douglas Currie，其目标是在月球上更大的范围内布置一些更为复杂的反射器。

与本周发射的“奋进”号航天飞机相比，这些月球计划可能不会引起多大关注，但是，当美国宇航局极力主张载人航天可以激励年轻人学习科学时，为月球计划而“奋进”的精神也正是它所要鼓励的。





Unit 20


TEXT ONE


Most cells are transparent—in other words, they are not very good at reflecting or absorbing light. To look at them under a microscope thus requires trickery. Many of these tricks kill the cells, and even those that keep them alive look only at slices through each cell, rather than seeing the whole thing in three dimensions.

Michael Feld, of the Massachusetts Institute of Technology, and his colleagues, think they can change that. They have invented a way to look at cells that are still alive. Moreover, they can do so in three dimensions. Their method is called tomographic phase microscopy, and it is reported in this week's Nature Methods. Instead of relying on absorbed or reflected light, Dr. Feld's technique celebrates transparency by looking at light that gets through unaltered. It does so by measuring a property called the refractive index.

This index measures the speed of light in a material. (Light zips along at the actual “speed of light”, faster than which nothing can go, only when it is travelling through a vacuum.) The different components of a cell, though transparent, have different refractive indices. Dr. Feld and his team therefore set out to map what these differences are, with a view to using them to distinguish between cellular components.

To measure the refractive indices of different parts of a cell they use a technique called interferometry, which involves splitting a beam of light in two. One half, known as the object beam, passes through the cell; the other is directed along a different path and acts as a reference. The length of the reference path is such that if no sample is present, the two daughter beams will be as perfectly in phase when they meet as they were when they were separated. The crests and the troughs of their waves will reinforce each other, and the result will be brightness. The more that the light passing through the sample is slowed down, however, the more the two beams will be out of phase. Crest will fall on trough, and the result will be darkness. It is this phase shift that gives Dr. Feld's new form of microscopy its name.

A single pair of beams does not, however, produce a useful image. To do that requires scanning the object beam through the target about a hundred different ways. From the refractive index of each path it is possible—with the application of some suitably crunchy computing power—to produce a three-dimensional image.

To test his idea, Dr. Feld looked at cervical-cancer cells. If you identify this cancer early, the patient will probably survive. Miss it, and she will die. Dr. Feld wondered if the changes that occur during cancer would show up using his new method. They did, in a part of the cell called the nucleolus. This is the place where the components of protein factories are made. Since cancer cells grow rapidly, and thus have a high demand for proteins, it was a likely place to expect changes.

Dr. Feld also has plans to use beams of different colours, since each colour has a slightly different refractive index in a given material. That would provide extra data for the computer to chew on, and probably result in better pictures. With enough pictures, Dr. Feld's technique may make biology as transparent as the cells it studies.

1. Tomographic phase microscopy is different from the other tricks that look at cells in that _____.

[A] the light that gets through the cells is unaltered in tomographic phase microscopy

[B] it does not require the trickery to kill cells

[C] it is not dependent on absorbed or reflected light

[D] it could see all the components of the cells from three dimensions

2. Which one of the following statements is TRUE of the speed of light in materials?

[A] Light runs the fastest when it passes through transparent materials in the real world.

[B] The speed of light can only be precisely measured when the light is traveling in vacuum.

[C] The speed of light in any material is slower than the actual “speed of light”.

[D] The speed of light shifts when the light travels through different cells.

3. The result of darkness in the technique of interferometry implies that _____.

[A] there is no light passing through the sample

[B] the refractive index of the sample is very great

[C] the speed of the light passing through the sample is very low

[D] the two daughter beams weaken each other

4. Dr. Feld's method could be applied into identifying cancer early by _____.

[A] detecting changes of refractive indices in the components of protein factories

[B] finding out the changes of the refractive indices in some parts of the cervical-cancer cells

[C] examining the changes of the refractive indices in the nucleolus

[D] identifying the changes of the refractive indices in part of the nucleolus of the cancer cells

5. The best title of the passage could be _____.

[A] Image of the Transparent Cells

[B] New Technique of Celebrating Transparency

[C] Refractive Indices of the Transparent Cells

[D] New Method of Detecting Cancer Cells





文章剖析


这篇文章讲述了Feld博士发明的一种观察透明活细胞的新方法。第一段讲述过去观察细胞的方法的弊端；第二段讲述新方法，即X线断层阶段显微法的大致情况；第三、第四和第五段讲述该方法的具体情况；第六段讲述Feld博士研究的方法可以用来检测癌细胞；第七段讲述Feld博士使用不同颜色的光束来得到更好的图像。





词汇注释


tomographic adj. X线断层的

interferometry n. 干涉测量

crunchy adj. 松脆的，易碎的

cervical adj. 子宫的

nucleolus n. 细胞核





难句突破


① Dr. Feld and his team therefore set out to map what these differences are, with a view to using them to distinguish between cellular components.

主体句式：Dr. Feld and his team... set out to...

结构分析：这是一个复合句，what引导的是宾语从句；with a view to...是句子的状语。

句子译文：Feld博士及其研究小组因此开始寻找这些不同，希望可以通过不同的折射率来辨别细胞的各种成分。

② To measure the refractive indices of different parts of a cell they use a technique called interferometry, which involves splitting a beam of light in two.

主体句式：... they use a technique...

结构分析：这是一个复合句，which引导的定语从句用来修饰前面的interferometry；不定式结构to...是目的状语。

句子译文：为了估测某一细胞不同组成部分的折射率，他们使用了一种叫干涉测量的方法，将一束光线一分为二。





题目分析


1. Tomographic phase microscopy is different from the other tricks that look at cells in that _____.

[A] the light that gets through the cells is unaltered in tomographic phase microscopy

[B] it does not require the trickery to kill cells

[C] it is not dependent on absorbed or reflected light

[D] it could see all the components of the cells from three dimensions

1. X线断层阶段显微法和其他观察细胞的方法的不同之处在于 _____。

[A] 穿过细胞的光在X线断层阶段显微法中是没有发生改变的

[B] 它不要求杀死细胞

[C] 它不依靠被吸收或反射的光

[D] 它可以从三个方位看到细胞的所有组成成分

答案：C　难度系数：☆☆☆

分析：细节题。选项A，第二段提到的是一些光穿过细胞时没有改变，但不代表所有的都没改变。选项B，根据第一段和第二段，该方法可以观察活细胞，但是之前的一些方法也可以观察活细胞，因此并不是二者的不同之处。选项C，第二段提到，该方法没有依靠被吸收或反射的光。选项D的内容文章中没有提到。因此，答案为C。

2. Which one of the following statements is TRUE of the speed of light in materials?

[A] Light runs the fastest when it passes through transparent materials in the real world.

[B] The speed of light can only be precisely measured when the light is traveling in vacuum.

[C] The speed of light in any material is slower than the actual “speed of light”.

[D] The speed of light shifts when the light travels through different cells.

2. 关于光在物质中的传播速度，下列哪个陈述是正确的？

[A] 光在穿过现实世界中的透明物体时的速度是最快的。

[B] 光速只有在真空状态下才能够被准确测量。

[C] 在任何物质中，光的速度都比“真正的光速”慢。

[D] 光穿过不同的细胞时，速度也会发生变化。

答案：C　难度系数：☆☆☆

分析：细节题。根据第三段，光在真空中速度最快，而真实世界中也存在真空，因此选项A是错误的。选项B的错误则在于，虽然其表述正确，但是却与题干要求讨论的“光在物质中的传播速度”无关。选项C，文章也提到了这点，没有别的物体的运行速度比光速快。选项D，光通过不同的细胞时，折射率不同，而与速度无关。因此，答案为C。

3. The result of darkness in the technique of interferometry implies that _____.

[A] there is no light passing through the sample

[B] the refractive index of the sample is very great

[C] the speed of the light passing through the sample is very low

[D] the two daughter beams weaken each other

3. 在干涉测量法中，黑暗的结果表示 _____。

[A] 没有光通过样本

[B] 样本的折射率很大

[C] 通过样本的光速很慢

[D] 两个子光束彼此削弱

答案：D　难度系数：☆

分析：推理题。根据第四段，当通过物体的光的速度减慢得越多，和另一束光束的异相程度就越大，波峰和波谷相互抵消，因此是黑暗的。因此，选项D最为符合。

4. Dr. Feld's method could be applied into identifying cancer early by _____.

[A] detecting changes of refractive indices in the components of protein factories

[B] finding out the changes of the refractive indices in some parts of the cervical-cancer cells

[C] examining the changes of the refractive indices in the nucleolus

[D] identifying the changes of the refractive indices in part of the nucleolus of the cancer cells

4. Feld博士的方法可以运用到早期发现癌症上，这要通过 _____来实现。

[A] 探测蛋白质工厂组成部分折射率的变化

[B] 发现部分子宫癌细胞中折射率的变化

[C] 探测细胞核中折射率的变化

[D] 找出部分癌细胞的细胞核中折射率的变化

答案：C　难度系数：☆☆

分析：根据第六段：They did, in a part of the cell called the nucleolus. This is the place where the components of protein factories are made. Since cancer cells grow rapidly, and thus have a high demand for proteins, it was a likely place to expect changes. 可知，Feld博士是在细胞核中发现了这种变化，因为癌细胞的生长需要大量的蛋白质，而细胞核是生产蛋白质的地方，因此，如果有变化就应该可以体现在细胞核中。所以，答案为C。

5. The best title of the passage could be _____.

[A] Image of the Transparent Cells

[B] New Technique of Celebrating Transparency

[C] Refractive Indices of the Transparent Cells

[D] New Method of Detecting Cancer Cells

5. 这篇文章最好的题目是 _____。

[A] 透明细胞的图像

[B] 研究透明的新技术

[C] 透明细胞的折射率

[D] 发现癌细胞的新方法

答案：B　难度系数：☆☆☆

分析：主旨题。这篇文章主要讲述了研究细胞折射率的新方法，通过这种新方法可以做许多研究，如细胞的样子和癌细胞的早期发现。因此，答案为B。





参考译文


大多数的细胞都是透明的，也就是说，它们没有很强的反射或吸收光的能力。因此，要在显微镜下看到它们就需要一定的技巧了。许多技巧都会杀死细胞，而那些能保证它们存活的技巧只能使人们看到各个细胞的切片，而不是从三维立体的角度来观察细胞。

麻省理工大学的Michael Feld及其同事认为他们可以改变这一点。他们发明了观察活细胞的方法，而且还可以观察到立体的细胞。他们的方法叫作X线断层阶段显微法，并刊登在本周的《自然方法》上。Feld博士不是通过那些被吸收或反射的光，而是利用了细胞透明特性，观察光穿过细胞后是否发生了改变。该方法是通过测量光的折射率来实现的。

折射率测量光在某种物质中的传播速度。（光只有在真空中时才以真正的“光速”来传播，比其他任何物体的速度都要快。）虽然细胞的不同成分是透明的，却有不同的折射率。Feld博士及其研究小组因此开始寻找这些不同，希望可以通过不同的折射率来辨别细胞的各种成分。

为了估测某一细胞不同组成部分的折射率，他们使用了一种叫干涉测量的方法，将一束光线一分为二，其中一束叫作物体光束，能穿过细胞；另外一束则沿着不同的路线前进，作为参照。参照路线的长度一定，如果没有物体，那么这两个光束就会同相，与它们分开时的情况一样。两束光的波峰和波谷会互相加强，结果就是形成了非常明亮的光。通过物体的光的速度减慢得越多，两个光束异相的程度就越大。此时，波峰会与波谷重合，最终结果就是黑暗。正是因为相的变化，Feld博士的新显微形式才有了自己的名称。

但是一对光束不会制造出有用的图像来。图像的生成需要将通过物体的光束以100种不同的方式来进行扫描。从每条路径的折射率，再运用一些适当的计算，就有可能可以生成三维图像。

为了验证他的想法，Feld博士研究了子宫癌细胞。越早辨认出该细胞，病人存活的几率就越大。如果忽略了该细胞，病人就会死亡。Feld博士想知道，使用自己的新方法是否能发现癌症期间的一些变化。他们在细胞核中发现了这种变化。细胞核是生产构成蛋白质的成分的地方。因为癌细胞的生长速度极快，因此需要大量的蛋白质，所以这里是最有可能发生改变的地方。

Feld博士还计划使用不同颜色的光束，因为每种颜色在某一物质中的折射率都略有不同。这就为计算机成像提供了更多的数据，而且可能会产生更好的图像。有了足够多的图像，Feld博士的技术就可以让生物学变得透明起来，就像他研究的那些透明细胞一样。





TEXT TWO


For a Nobel laureate, the molecular biologist Max Perutz made a lot of mistakes. His science was strewn with assertions that were not supported by the sparse evidence he had gathered. No matter. He was eventually right about the important things—and gentleman enough to concede his errors.

With bloody-minded persistence, Perutz mastered the painstaking task of analysing images of haemoglobin, the component of blood that carries oxygen. This was no mean feat: a molecule of haemoglobin consists of thousands of atoms and, at the time, only simple structures of tens of atoms had been mapped. It was for this work that Perutz was awarded the Nobel Prize in chemistry in 1962. But his triumphal announcement of the correct structure of haemoglobin was by no means his first solution to the problem: he had previously claimed all sorts of unlikely arrangements, backing down each time a colleague spotted a fatal flaw.

Even when he did finally hold the secret to why blood supports life, he did not piece together the evidence to produce the ultimate result. Indeed, Perutz was furious when a junior researcher saw how the final piece fitted and could not resist popping it into its slot, completing what Perutz viewed as his jigsaw puzzle. Nevertheless, it was Perutz who had gathered all the pieces and who ensured, in the end, that they were correctly assembled.