『新东方在线托福阅读』为托福考生准备了ETS托福TPO/Official 10 Passage 2阅读练习：What is the author’s purpose in presenting the information in paragraph 7?真题题目及答案解析，TPO/Official 10 Passage 2阅读原文范文音频翻译

托福TPO/Official 10 Passage 2阅读原文What is the author’s purpose in presenting the information in paragraph 7?题目答案及解析-新东方托福官方网校手机版

决定当前气候问题是否揭示人类活动影响的证据的最困难方面之一是，很难对构成气候自然变化的因素进行度量。

One of the most difficult aspects of deciding whether current climatic events reveal evidence of the impact of human activities is that it is hard to get a measure of what constitutes the natural variability of the climate.

我们知道，在过去的几千年中，在没有任何人工重大干预的情况下，气候发生了重大变化。

We know that over the past millennia the climate has undergone major changes without any significant human intervention.

我们还知道，全球气候系统非常复杂，并且所有事物都以某种方式联系在一起，因此该系统能够以意想不到的方式波动。

We also know that the global climate system is immensely complicated and that everything is in some way connected, and so the system is capable of fluctuating in unexpected ways.

因此，我们需要知道气候可以自行改变多少，以便有把握地解释近期变化的自然程度，而不是人类活动的结果。

We need therefore to know how much the climate can vary of its own accord in order to interpret with confidence the extent to which recent changes are natural as opposed to being the result of human activities.

仪器记录的年代还远远不够，无法为我们提供超过一个世纪的时间尺度上全球气候变化的可靠测量结果。

Instrumental records do not go back far enough to provide us with reliable measurements of global climatic variability on timescales longer than a century.

我们所知道的是，随着更长的时间间隔，记录会显示越来越多的证据表明不同朝代之间气候的缓慢波动。

What we do know is that as we include longer time intervals, the record shows increasing evidence of slow swings in climate between different regimes.

为了更清楚地了解更为久远的波动情况，我们需要使用替代性记录。

To build up a better picture of fluctuations appreciably further back in time requires us to use proxy records.

在很长的一段时间内，物质的物理和化学性质随当时的气候而变化，它们以系统的方式沉积，以提供这些性质随时间变化的连续记录，有时长达数百或数千年。

Over long periods of time, substances whose physical and chemical properties change with the ambient climate at the time can be deposited in a systematic way to provide a continuous record of changes in those properties over time, sometimes for hundreds or thousands of years.

通常，分层每年进行一次，因此我们可以根据记录中观察到的变化来确定时间。

Generally, the layering occurs on an annual basis, hence the observed changes in the records can be dated.

可以从属性的系统变化推断出的有关温度，降雨量和其他气候信息的信息通常称为替代性数据。

Information on temperature, rainfall, and other aspects of the climate that can be inferred from the systematic changes in properties is usually referred to as proxy data.

替代性温度记录是根据格陵兰中部冰盖上钻出的冰芯，西欧分层湖沉积物中嵌入的方解石壳，热带大西洋的海底沉积物芯，秘鲁冰川的冰芯以及南极洲东部的冰芯重建的。

Proxy temperature records have been reconstructed from ice core drilled out of the central Greenland ice cap, calcite shells embedded in layered lake sediments in Western Europe, ocean floor sediment cores from the tropical Atlantic Ocean, ice cores from Peruvian glaciers, and ice cores from eastern Antarctica.

虽然这些记录提供了大致一致的迹象，表明温度变化可能在全球范围内发生，但是仍然存在一些有趣的差异，这表明区域气候中温度变化的模式也可以彼此显著不同。

While these records provide broadly consistent indications that temperature variations can occur on a global scale, there are nonetheless some intriguing differences, which suggest that the pattern of temperature variations in regional climates can also differ significantly from each other.

替代性记录清楚地表明，在几千年以上的时间范围内，气候发生了重大自然变化

What the proxy records make abundantly clear is that there have been significant natural changes in the climate over timescales longer than a few thousand years.

然而，同样惊人的是过去10,000年（全新世时期）气候的相对稳定性。

Equally striking, however, is the relative stability of the climate in the past 10,000 years (the Holocene period).

从这些记录对全球气候的覆盖范围可以衡量其真实变化的程度来看，它至少应表明气候变化的所有自然原因是如何结合在一起的。

To the extent that the coverage of the global climate from these records can provide a measure of its true variability, it should at least indicate how all the natural causes of climate change have combined.

这些包括大气的混乱波动，海洋的缓慢但同样不稳定的行为，陆地表面的变化以及冰雪的覆盖范围。

These include the chaotic fluctuations of the atmosphere, the slower but equally erratic behavior of the oceans, changes in the land surfaces, and the extent of ice and snow.

还包括火山活动，太阳活动以及可能的人类活动引起的任何变化。

Also included will be any variations that have arisen from volcanic activity, solar activity, and, possibly, human activities.

估算导致气候变化的所有各种过程如何结合的一种方法是使用全球气候的计算机模型。

One way to estimate how all the various processes leading to climate variability will combine is by using computer models of the global climate.

它们只能代表全球气候的全部复杂性，因此只能提供有限的有关自然变异性的信息。

They can do only so much to represent the full complexity of the global climate and hence may give only limited information about natural variability.

研究表明，迄今为止，计算机模拟中的变异性比从替代性记录中获得的数据要小得多。

Studies suggest that to date the variability in computer simulations is considerably smaller than in data obtained from the proxy records.

除了全球气候系统本身的内部可变性之外，还有诸如火山和太阳活动等外部影响的附加因素。

In addition to the internal variability of the global climate system itself, there is the added factor of external influences, such as volcanoes and solar activity.

越来越多的人认为，这两种物理变化都会对气候产生可测量的影响。

There is a growing body of opinion that both these physical variations have a measurable impact on the climate.

因此，我们需要能够将这些纳入我们的审议中。

Thus we need to be able to include these in our deliberations.

当前的一些分析得出的结论是，火山和太阳活动解释了从十七世纪到二十世纪初这段时期观测到的相当多的变化，但是不能援引它们来解释近几十年来的迅速变暖。

Some current analyses conclude that volcanoes and solar activity explain quite a considerable amount of the observed variability in the period from the seventeenth to the early twentieth centuries, but that they cannot be invoked to explain the rapid warming in recent decades.

According to paragraph 1, which of the following must we find out in order to determine the impact of human activities upon climate?

According to paragraph 2, an advantage of proxy records over instrumental records is that

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.

According to paragraph 3, scientists are able to reconstruct proxy temperature records by

According to paragraphs 3 and 4, proxy data have suggested all of the following about the climate EXCEPT:

All of the following are mentioned in paragraph 5 as natural causes of climate change EXCEPT

According to paragraph 6 which of the following is true of computer models of the global climate?

What is the author’s purpose in presenting the information in paragraph 7?

Look at the four squares  that indicate where the following sentence could be added to the passage. Indeed, the contribution of volcanoes and solar activity would more likely have been to actually reduce the rate of warming slightly.  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.

Variations in the Climate One of the most difficult aspects of deciding whether current climatic events reveal evidence of the impact of human activities is that it is hard to get a measure of what constitutes the natural variability of the climate. We know that over the past millennia the climate has undergone major changes without any significant human intervention. We also know that the global climate system is immensely complicated and that everything is in some way connected, and so the system is capable of fluctuating in unexpected ways. We need therefore to know how much the climate can vary of its own accord in order to interpret with confidence the extent to which recent changes are natural as opposed to being the result of human activities. Instrumental records do not go back far enough to provide us with reliable measurements of global climatic variability on timescales longer than a century. What we do know is that as we include longer time intervals, the record shows increasing evidence of slow swings in climate between different regimes. To build up a better picture of fluctuations appreciably further back in time requires us to use proxy records. Over long periods of time, substances whose physical and chemical properties change with the ambient climate at the time can be deposited in a systematic way to provide a continuous record of changes in those properties over time, sometimes for hundreds or thousands of years. Generally, the layering occurs on an annual basis, hence the observed changes in the records can be dated. Information on temperature, rainfall, and other aspects of the climate that can be inferred from the systematic changes in properties is usually referred to as proxy data. Proxy temperature records have been reconstructed from ice core drilled out of the central Greenland ice cap, calcite shells embedded in layered lake sediments in Western Europe, ocean floor sediment cores from the tropical Atlantic Ocean, ice cores from Peruvian glaciers, and ice cores from eastern Antarctica. While these records provide broadly consistent indications that temperature variations can occur on a global scale, there are nonetheless some intriguing differences, which suggest that the pattern of temperature variations in regional climates can also differ significantly from each other. What the proxy records make abundantly clear is that there have been significant natural changes in the climate over timescales longer than a few thousand years. Equally striking, however, is the relative stability of the climate in the past 10,000 years (the Holocene period). To the extent that the coverage of the global climate from these records can provide a measure of its true variability, it should at least indicate how all the natural causes of climate change have combined. These include the chaotic fluctuations of the atmosphere, the slower but equally erratic behavior of the oceans, changes in the land surfaces, and the extent of ice and snow. Also included will be any variations that have arisen from volcanic activity, solar activity, and, possibly, human activities. One way to estimate how all the various processes leading to climate variability will combine is by using computer models of the global climate. They can do only so much to represent the full complexity of the global climate and hence may give only limited information about natural variability. Studies suggest that to date the variability in computer simulations is considerably smaller than in data obtained from the proxy records. In addition to the internal variability of the global climate system itself, there is the added factor of external influences, such as volcanoes and solar activity.  There is a growing body of opinion that both these physical variations have a measurable impact on the climate.  Thus we need to be able to include these in our deliberations.  Some current analyses conclude that volcanoes and solar activity explain quite a considerable amount of the observed variability in the period from the seventeenth to the early twentieth centuries, but that they cannot be invoked to explain the rapid warming in recent decades.