求助~tpo10阅读第二篇几个问题~

皇甫秋荻UID: 2638790

1. Paragraph 1： 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.
本段最后一句是什么意思呢，句子好长，看不懂了。。。

2. Paragraph 4： 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).
本段为什么前面讲气候变化快，后面又将气候相对来说比较稳定呢。。。

3. Paragraph 2：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.

② According to paragraph 2, an advantage of proxy records over instrumental records is that
A.
they are more-reliable measures of climatic variability in the past century.
C.
they provide information on climate fluctuations further back in time.
我选的是A，答案是C。 我老感觉两个都对。。。

4. Paragraph 3：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 overtime, 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.

④ According to paragraph 3, scientists are able to reconstruct proxy temperature records by
A.
studying regional differences in temperature variations
B.
studying and dating changes in the properties of substances
我选的是A，答案是B。我还是觉得两个都对。。。=。=

这篇阅读做的好纠结，恳请各位大侠帮忙~ 多谢~

xiongcan818UID: 2849571

第四题：A错，B对
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 data其实就是一些物质的属性。
A选项中 studying regional differences in temperature variations 其实只是表面的，关键还是到各个地点去搜集properties 然后根据这些properties给出结论：While these records provide broadly consistent indications that temperature variations can occur on a global scale,。。。

呵呵，我就先答这个，其他同学继续上。。。呵呵