扫描二维码，直接登录
题库 / OG2016-RC-11
Io and Europa, the inner two of Jupiter's four largest moons, are about the size of Earth's moon and are composed mostly or entirely of rock and metal. Ganymede and Callisto are larger and roughly half ice. Thus, these four moons are somewhat analogous to the planets of the solar system, in which the rock- and metal-rich inner planets are distinct from the much larger gas and ice-rich outer planets. Jupiter's moons are, however, more "systematic": many of their properties vary continuously with distance from Jupiter. For example, Io is ice-free, Europa has a surface shell of ice, and while Ganymede and Callisto are both ice-rich, outermost Callisto has more.
This compositional gradient has geological parallels. Io is extremely geologically active, Europa seems to be active on a more modest scale, and Ganymede has undergone bouts of activity in its geological past. Only Callisto reveals no geological activity. In similar fashion, Callisto's surface is very heavily cratered from the impact of comets and asteroids; Ganymede, like Earth's moon, is heavily cratered in parts; Europa is very lightly cratered; and no craters have been detected on Io, even though Jupiter's gravity attracts comets and asteroids passing near it, substantially increasing the bombardment rate of the inner moons compared to that of the outer ones. But because of Io's high degree of geological activity, its surface undergoes moreor- less continuous volcanic resurfacing.
According to the passage, the difference in the amount of cratering on Callisto's and Io's respective surfaces can probably be explained by the difference between these two moons with respect to which of the following factors?
Size
Ice content
The rate of bombardment by comets and asteroids
The influence of Jupiter's other moons
The level of geological activity
此讲解的内容由AI生成，还未经人工审阅，仅供参考。
答案：E. The level of geological activity
解释：文章指出，在太阳系中，内部岩石和金属富集的行星很容易受到并受到影响的小行星和彗星的撞击，导致它们表面有很多的陨石坑。但是，Io表面几乎没有任何陨石坑，因为它有很高的地质活动水平，不断重新建设其海绵层。这就是为什么E. Level of geological activity是正确答案。
18OG428. A strange method
of questioning
the first question corespond with the last sentence in the passage!＠x＠
一定要注意梳理文章的结构：总分/对比+深入某一个/一整条时间线等等
留意每一次的转折
no craters have been detected on Io, even though Jupiter's gravity attracts comets and asteroids passing near it, substantially increasing the bombardment rate of the inner moons compared to that of the outer ones. But because of Io's high degree of geological activity, its surface undergoes moreor- less continuous volcanic resurfacing.
介绍了Jupiter的四个月亮：lo, Europa, G and C.他们的成分分别是：大部分的岩石和金属（前两个），一半以上是冰（后两个）；冰的覆盖情况，lo没有冰，Europa表面一层冰，另外两个好多冰； 介绍四者的地理活跃性：他们按顺序排列，C最不活跃；最后比较四者表面的裂痕或坑的情况，四者依次递增，lo没有撞坑，因为它的高活跃性。
在CE之前错选C，Mark一下我的理解
in similar fashion表示同理而言，和前面的活跃程度对应，导致不同行星的弹坑数量不同；
最后一句but because因为地质活动频繁，反而留下的弹坑较少。
. But because 定位！
bout爆发 发作 一个回合 一阵
Crater 形成坑
主要是没看懂最后一句，resurface重塑
But because of Io's high degree of geological activity, its surface undergoes moreor- less continuous volcanic resurfacing.
虽然离得最近的lo
The rate of bombardment by comets and asteroids更高
但是由于地质活动多，表面不停地进行重塑，反而留下的坑比较少
注意审题。
问的是can probably be explained by the difference between these two moons with respect to which of the following factors
http://gmat.xdf.cn/201509/10348908.html
问题问的是the difference in the amount of cratering。第二段陈述了是因为geological activity的程度， Io is extremely geologically active, Europa seems to be active on a more modest scale, and Ganymede has undergone bouts of activity in its geological past. Only Callisto reveals no geological activity.
细节1，用名字和crater定位