GWD17-Q35 to Q37问题求解

fdunan

When a large body strikes a planet or moon, material is ejected, thereby creating a hole in the planet and a local deficit of mass.  This deficit shows up as a gravity anomaly:  the removal of the material that has been ejected to make the hole results in an area of slightly lower gravity than surrounding areas.  One would therefore expect that all of the large multi-ring impact basins on the surface of Earth’s Moon would show such negative gravity anomalies, since they are, essentially, large holes in the lunar surface.  Yet data collected in 1994 by the Clementine spacecraft show that many of these lunar basins have no anomalously low gravity and some even have anomalously high gravity.  Scientists speculate that early in lunar history, when large impactors struck the Moon’s surface, causing millions of cubic kilometers of crustal debris to be ejected, denser material from the Moon’s mantle rose up beneath the impactors almost immediately, compensating for the ejected material and thus leaving no low gravity anomaly in the resulting basin.  Later, however, as the Moon grew cooler and less elastic, rebound from large impactors would have been only partial and incomplete.  Thus today such gravitational compensation probably would not occur:  the outer layer of the Moon is too cold and stiff.

36. Q36:
The passage suggests that if the scientists mentioned in line 19 are correct in their speculations, the large multi-ring impact basins on the Moon with the most significant negative gravity anomalies probably
A.    were not formed early in the Moon’s history
B.    were not formed by the massive ejection of crustal debris
C.    are closely surrounded by other impact basins with anomalously low gravity
D.    were created by the impact of multiple large impactors
E.    were formed when the Moon was relatively elastic

答案选A好像正好反了，应该选E吧

fdunan

后面有句话“Thus today such gravitational compensation probably would not occur:  the outer layer of the Moon is too cold and stiff.”更是说明basin是早期形成的，那个时候比较有弹性。

Bobopauline

我也觉得是E

wangquan0322

我觉得这题选A,我们应该注意到一个词“yet”，yet data collected in 1994 by...,这里的yet表明了和前文的意思相反，达到了取反的作用，所以后面的scientists所研究的结果应该是与前文不一致的，而前文说了multi-ring impact basins on the surface ....show such negative gravity anomalies ...与提干一致，所以在这里科学家应该否定之前的结论，故选A