『新东方在线托福阅读』为托福考生准备了ETS托福TPO/Official 22 Passage 3阅读练习：In paragraph 6, why does the author mention that “the Sun has many more atoms of any element, say iron, than does a meteorite specimen”?真题题目及答案解析，TPO/Official 22 Passage 3阅读原文范文音频翻译

托福TPO/Official 22 Passage 3阅读原文In paragraph 6, why does the author mention that “the Sun has many more atoms of any element, say iron, than does a meteorite specimen”?题目答案及解析-新东方托福官方网校手机版

1969年2月8日午夜某个时候，一颗大而明亮的流星进入地球大气层，破裂成千上万块，坠落到地面，并散布在墨西哥奇瓦瓦州内一片长50英里、宽10英里的区域。

Sometime after midnight on February 8, 1969, a large, bright meteor entered Earth’s atmosphere and broke into thousands of pieces, plummeted to the ground, and scattered over an area 50 miles long and 10 miles wide in the state of Chihuahua in Mexico.

这次降临的第一个陨石是在Pueblito de Allende村发现的。

The first meteorite from this fall was found in the village of Pueblito de Allende.

总共人们大约发现了约两吨的陨石碎片，所有碎片均以第一次发现的地区阿连德的名字命名。

Altogether, roughly two tons of meteorite fragments were recovered, all of which bear the name Allende for the location of the first discovery.

阿连德的各个标本上覆盖着进入地球大气层被减速时外表融化而形成的黑色的玻璃状硬皮。

Individual specimens of Allende are covered with a black, glassy crust that formed when their exteriors melted as they were slowed by Earth’s atmosphere.

当阿连德陨星破碎之后，人们发现其中包含了各种小的、独特的物体，形状为球形或不规则形状，并嵌入深灰色的基质（组合材料）中，该基质曾经是太阳星云的组成部分，即那些形成了我们的太阳系的星际气体云和尘埃。

When broken open, Allende stones are revealed to contain an assortment of small, distinctive objects, spherical or irregular in shape and embedded in a dark gray matrix (binding material), which were once constituents of the solar nebula—the interstellar cloud of gas and dust out of which our solar system was formed.

阿连德陨石被归类为球粒陨石。

The Allende meteorite is classified as a chondrite.

球粒陨石的名字取自希腊语chondros（意思是“种子”），这暗示着它们的外观为含有微小种子的岩石。

Chondrites take their name from the Greek word chondros—meaning “seed”—an allusion to their appearance as rocks containing tiny seeds.

这些种子实际上是球状晶体：毫米大小的硅酸盐材料熔化的小滴，被冷却成玻璃和晶体的球体。

These seeds are actually chondrules: millimeter-sized melted droplets of silicate material that were cooled into spheres of glass and crystal.

一些陨石球粒含有在熔化事件中幸存下来的晶粒，因此，这些神秘的颗粒一定是在当密密麻麻的星云尘埃团在高温（接近1,700摄氏度）下熔化，并且在那些颗粒能够融化之前就冷却下来时形成的。

A few chondrules contain grains that survived the melting event, so these enigmatic chondrules must have formed when compact masses of nebular dust were fused at high temperatures—approaching 1,700 degrees Celsius—and then cooled before these surviving grains could melt.

对颗粒的纹理的研究证实，它们在几分钟或几小时内测得的时间中冷却得相当快，因此形成它们的加热事件一定是局部的。

Study of the textures of chondrules confirms that they cooled rather quickly, in times measured in minutes or hours, so the heating events that formed them must have been localized.

将大部分星云加热到如此极端的温度似乎不太可能，而且巨大的星云区域不可能如此快地散失热量。

It seems very unlikely that large portions of the nebula were heated to such extreme temperatures, and huge nebula areas could not possibly have lost heat so fast.

陨石颗粒一定是在那些能够迅速散失热量的小块星云中融化的。

Chondrules must have been melted in small pockets of the nebula that were able to lose heat rapidly.

这些奇特的玻璃球体的起源仍然是一个谜。

The origin of these peculiar glassy spheres remains an enigma.

阿连德同样令人困惑的成分是耐火夹杂物：这是一种不规则的白色团块，往往比陨石颗粒大。

Equally perplexing constituents of Allende are the refractory inclusions: irregular white masses that tend to be larger than chondrules.

它们由地球上不常见的矿物质组成，它们都富含钙，铝和钛元素，这三种是星云中主要元素中最难熔的（耐熔化）。

They are composed of minerals uncommon on Earth, all rich in calcium, aluminum, and titanium, the most refractory (resistant to melting) of the major elements in the nebula.

和耐火夹杂物中出现的相同矿物被认为是最早从太阳星云中冷凝出来的物质。

The same minerals that occur in refractory inclusions are believed to be the earliest-formed substances to have condensed out of the solar nebula.

然而，对夹杂物质地的研究表明，矿物在夹杂物中出现的顺序因夹杂物而异，并且通常与这些金属的理论冷却顺序不符。

However, studies of the textures of inclusions reveal that the order in which the minerals appeared in the inclusions varies from inclusion to inclusion, and often does not match the theoretical condensation sequence for those metals.

球状晶体基质将阿连德的球状晶体和内含物结合在一起，这是一种细粒的，主要为硅酸盐矿物的物质所组成的，其中同时也包括铁金属和硫化铁晶粒。

Chondrules and inclusions in Allende are held together by the chondrite matrix, a mixture of fine-grained, mostly silicate minerals that also includes grains of iron metal and iron sulfide.

曾一度有人认为这些基体颗粒可能是原始的星状尘埃，即制造陨石颗粒和夹杂物的原料。

At one time it was thought that these matrix grains might be pristine nebular dust, the sort of stuff from which chondrules and inclusions were made.

但是，对球粒陨石基质的详细研究表明，尽管少量的幸存星际尘埃与加工过的物质混合，但其中的大部分也是由星云中的凝结或熔化形成的。

However, detailed studies of the chondrite matrix suggest that much of it, too, has been formed by condensation or melting in the nebula, although minute amounts of surviving interstellar dust are mixed with the processed materials.

所有这些不同的成分聚集在一起，形成颗粒状的陨石（例如阿连德），其化学成分非常类似于太阳。

All these diverse constituents are aggregated together to form chondritic meteorites, like Allende, that have chemical compositions much like that of the Sun.

为了比较陨石和太阳的组成，我们必须使用元素的比率，而不是简单地使用原子的丰富度。

To compare the compositions of a meteorite and the Sun, it is necessary that we use ratios of elements rather than simply the abundances of atoms.

毕竟，太阳中任何元素（例如铁）的原子都比陨石样品中的原子多得多，但两种物质中铁与硅的比率可能是可比的。

After all, the Sun has many more atoms of any element, say iron, than does a meteorite specimen, but the ratios of iron to silicon in the two kinds of matter might be comparable.

The compositional similarity is striking.

主要的区别在于，相对于太阳，阿连德（Allende）缺乏最易挥发的元素，例如氢，碳，氧，氮和稀有气体。

The major difference is that Allende is depleted in the most volatile elements, like hydrogen, carbon, oxygen, nitrogen, and the noble gases, relative to the Sun.

这些是即使在非常低的温度下也易于形成气体的元素。

These are the elements that tend to form gases even at very low temperatures.

我们可能认为球粒陨石是一个蒸馏过的太阳的样本，蒸馏过的太阳是一种仅去除气体的太阳渣。

We might think of chondrites as samples of distilled Sun, a sort of solar sludge from which only gases have been removed.

由于几乎所有太阳系的质量都位于太阳中，因此化学上的这种相似性意味着，球粒陨石，除最易挥发的元素以外，拥有太阳系的平均组成成分；它们是真正的星云状团块，其成分可能类似于组成行星的物质。

Since practically all the solar system’s mass resides in the Sun, this similarity in chemistry means that chondrites have average solar system composition, except for the most volatile elements; they are truly lumps of nebular matter, probably similar in composition to the matter from which planets were assembled.

The word “location” in the passage is closest in meaning to

Which of the following can be inferred from paragraph 1 about the large meteor that entered Earth’s atmosphere on February 8, 1969?

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

The word “allusion” in the passage is closest in meaning to

The word “enigmatic” in the passage is closest in meaning to

According to paragraph 3, what does the presence of grains inside some of the chondrules indicate?

According to paragraph 4, all of the following are true about the minerals found in the refractory inclusions EXCEPT:

The word “pristine” in the passage is closest in meaning to

According to paragraph 5, which of the following is indicated by studies of the mixture holding the inclusions together?

In paragraph 6, why does the author mention that “the Sun has many more atoms of any element, say iron, than does a meteorite specimen”?

According to paragraph 6, the composition of chondritic meteorites differs from the composition of the Sun primarily in

According to paragraph 6, what is the significance of the similarity in composition between chondrites and the Sun?

Look at the four squares  that indicate where the following sentence could be added to the passage. It is therefore still unclear if all inclusions were formed in the same way.  Where would the sentence best fit? Click on a square  to add the sentence to the passage.

Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

The Allende Meteorite Sometime after midnight on February 8, 1969, a large, bright meteor entered Earth’s atmosphere and broke into thousands of pieces, plummeted to the ground, and scattered over an area 50 miles long and 10 miles wide in the state of Chihuahua in Mexico. The first meteorite from this fall was found in the village of Pueblito de Allende. Altogether, roughly two tons of meteorite fragments were recovered, all of which bear the name Allende for the location of the first discovery. Individual specimens of Allende are covered with a black, glassy crust that formed when their exteriors melted as they were slowed by Earth’s atmosphere. When broken open, Allende stones are revealed to contain an assortment of small, distinctive objects, spherical or irregular in shape and embedded in a dark gray matrix (binding material), which were once constituents of the solar nebula—the interstellar cloud of gas and dust out of which our solar system was formed. The Allende meteorite is classified as a chondrite. Chondrites take their name from the Greek word chondros—meaning “seed”—an allusion to their appearance as rocks containing tiny seeds. These seeds are actually chondrules: millimeter-sized melted droplets of silicate material that were cooled into spheres of glass and crystal. A few chondrules contain grains that survived the melting event, so these enigmatic chondrules must have formed when compact masses of nebular dust were fused at high temperatures—approaching 1,700 degrees Celsius—and then cooled before these surviving grains could melt. Study of the textures of chondrules confirms that they cooled rather quickly, in times measured in minutes or hours, so the heating events that formed them must have been localized. It seems very unlikely that large portions of the nebula were heated to such extreme temperatures, and huge nebula areas could not possibly have lost heat so fast. Chondrules must have been melted in small pockets of the nebula that were able to lose heat rapidly. The origin of these peculiar glassy spheres remains an enigma. Equally perplexing constituents of Allende are the refractory inclusions: irregular white masses that tend to be larger than chondrules.  They are composed of minerals uncommon on Earth, all rich in calcium, aluminum, and titanium, the most refractory (resistant to melting) of the major elements in the nebula.  The same minerals that occur in refractory inclusions are believed to be the earliest-formed substances to have condensed out of the solar nebula.  However, studies of the textures of inclusions reveal that the order in which the minerals appeared in the inclusions varies from inclusion to inclusion, and often does not match the theoretical condensation sequence for those metals.  Chondrules and inclusions in Allende are held together by the chondrite matrix, a mixture of fine-grained, mostly silicate minerals that also includes grains of iron metal and iron sulfide. At one time it was thought that these matrix grains might be pristine nebular dust, the sort of stuff from which chondrules and inclusions were made. However, detailed studies of the chondrite matrix suggest that much of it, too, has been formed by condensation or melting in the nebula, although minute amounts of surviving interstellar dust are mixed with the processed materials. All these diverse constituents are aggregated together to form chondritic meteorites, like Allende, that have chemical compositions much like that of the Sun. To compare the compositions of a meteorite and the Sun, it is necessary that we use ratios of elements rather than simply the abundances of atoms. After all, the Sun has many more atoms of any element, say iron, than does a meteorite specimen, but the ratios of iron to silicon in the two kinds of matter might be comparable. The compositional similarity is striking. The major difference is that Allende is depleted in the most volatile elements, like hydrogen, carbon, oxygen, nitrogen, and the noble gases, relative to the Sun. These are the elements that tend to form gases even at very low temperatures. We might think of chondrites as samples of distilled Sun, a sort of solar sludge from which only gases have been removed. Since practically all the solar system’s mass resides in the Sun, this similarity in chemistry means that chondrites have average solar system composition, except for the most volatile elements; they are truly lumps of nebular matter, probably similar in composition to the matter from which planets were assembled.