OG-14

gigiga0118

80The primary focus of the passage is on which of the following?
(A) Comparing two scientific theories and contrasting the predictions that each would make concerning a natural phenomenon
(B) Describing a new theoretical model and noting that it explains the nature of observations made of a particular natural phenomenon
(C) Evaluating the results of a particular scientific experiment and suggesting further areas for research
(D) Explaining how two different natural phenomena are related and demonstrating a way to measure them
(E) Analyzing recent data derived from observations of an actual phenomenon and constructing a model to explain the data

我的問題在A

Comparing two scientific theories and contrasting the predictions that each would make concerning a natural phenomenon

og認為錯在後面,文中沒有進行contrast

這我理解

那麼

1.文中有在做compare嗎??

我找不出在哪裡阿??

2關於A選項的意思我實在不太清楚

可以解釋一下嗎??

ring_cheng

Astronomers have hypothesized (老观点认为broaden with time，注意时态表示过去）that a meteor stream should broaden with time as the dust particles’ individual orbits are perturbed by planetary gravitational fields.

A recent computer-modeling experimetn tested this hypothesis by tracking the influence of planetary gravitation over a projected 5,000-year period on the positions of a group of hypothetical dust particles. In the model, the particles were randomly distributed throughout a computer simulation of the orbit of an actual meteor stream, the Geminid. The researcher found, as expected,that the computer-model stream broadened with time. (新研究证明了老观点，recent）

Coventional theories,（前指认为broaden with time的老观点-进一步提出老观点认为中间厚两边薄） however, predicted that the distribution of particles would be increaingly dense toward the center of a meteor stream.

Surpringly, the computer-model meteor stream gradually came to resemble a thick-walled, hollow pipe.（转折，该实验发现-中空而壁厚，与老观点相反）

我觉得这里主要是说明从实验中得出的意外的新发现（虽然它与原理论相反），而用这个新发现来解释流星雨的双峰现象。文章原意不在比较。

思谦

请教passage 14中的

80. The primary fcuse of the passage is on which of the

following？

（B)Describing a new theoretical model and nothing

that it explains the nature of obsservations  

made of a particularnatural phenomenon.

请问这个B中的nothing that……后面为什么放在这，是什么意思，请解释一下，谢谢！

wangyu73cn

noting

xixi2004

87题的E看得不大明白：为什么3000年是5000年的精确描述呢？请指点一下。谢谢！

xixi2004

没人理，顶一下。

z520m

因为模型推断如果GEminid的年龄是5000岁的话，那么穿越GEminid要24小时以上（over a day），实际来讲只用了19小时（line 39）,那么根据模型对地球穿越GEminid速度的判断，GEminid得年龄大约是3000 years.所以前提就是模型对GEminid的判断没有问题，如果有问题，那么不能得出GEminid的年龄。

toto2004

很清楚，谢谢!

fuyun

有个问题想不通。

There is no reason why the Earth should always pass through the stream’s exact center, so the time interval between the two bursts of activity would vary from one year to the next.这段话说地球不一定每次都是从星河中间穿过，所以两次流星雨高峰之间的间隔时间不同。

可是后面又说平均穿越时间是19小时，不确定地球是从哪个地方穿越星河，也许每次都离中心很远说不定，怎么可以根据这个平均时间来确定Geminid的年龄呢？

月桂女神

这个文章各段的逻辑关系是什么呀~我看了半天觉得特别混乱亚~希望牛牛指点哦~