Thanks, dorbear gg! Recently I can't visit CD frequently, but I will be back after test. CD is a wonderful land because of our dear hosters' hard working!
以下是引用dorbear在2003-10-8 11:46:00的发言： 60. One of the more reliable methods of determining regional climatic conditions in prehistoric periods is to examine plant pollen trapped in glacial ice during ancient times. By comparing such pollen samples with spores take from modern vegetation, scientists can figure out approximately what the weather was like at the time of pollen deposition. Furthermore, by submitting the prehistoric samples to radiocarbon dating techniques, we can also determine when certain climatic conditions were prevalent in that portion of the globe. Which one of the following may be inferred from the information in the passage? (A) The earth has undergone several glacial periods. (B) Radiocarbon dating can be corroborated by glacial evidence. (C) Similarities between prehistoric and contemporary climates do not exist. (D) Pollen deposition is a fairly continuous process. (E) Certain flora are reliably associated with particular climatic conditions.
answer is: e, why b can't be. ============================== 文中只是提到用到同位素测定，并没有得到任何如何证实这种确认。所以B不是选项。E实际上本题的假设条件，所有的假设条件都是一个有效推论。
我看了注解：
Argument: A ——B. Ask for inference C. The links are A -B -C. Or Not C-Not B. A and B are the premise and conclusion in the argument respectively. C is the inference. 推论
60. One of the more reliable methods of determining regional climatic conditions in prehistoric periods is to examine plant pollen trapped in glacial ice during ancient times. By comparing such pollen samples with spores take from modern vegetation, scientists can figure out approximately what the weather was like at the time of pollen deposition. Furthermore, by submitting the prehistoric samples to radiocarbon dating techniques, we can also determine when certain climatic conditions were prevalent in that portion of the globe. Which one of the following may be inferred from the information in the passage? (A) The earth has undergone several glacial periods. (B) Radiocarbon dating can be corroborated by glacial evidence. (C) Similarities between prehistoric and contemporary climates do not exist. (D) Pollen deposition is a fairly continuous process. (E) Certain flora are reliably associated with particular climatic conditions.
With pollen samples, you are trying to deduce the weather conditions. With radiocarbon dating, you are trying to deduce the date. They are independent techniques and give different results.
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