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Q35 to Q37:
(This passage was excerpted from material
published in 1996.)
When a large body strikes a planet
or moon, material is ejected, thereby
creating a hole in the planet and a local
Line deficit of mass. This deficit shows up
(5) 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
(10) 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
(15) 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
(20) 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
(25) beneath the impactors almost imme-
diately, compensating for the ejected
material and thus leaving no low gravity
anomaly in the resulting basin. Later,
however, as the Moon grew cooler
(30) 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.
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Q35:
According to the passage, the gravitational compensation referred to in line 33 is caused by which of the following?
- A deficit of mass resulting from the creation of a hole in the lunar surface
- The presence of material from the impactor in the debris created by its impact
- The gradual cooling and stiffening of the Moon’s outer layer
- The ejection of massive amounts of debris from the Moon’s crust
- The rapid upwelling of material from the lunar mantle
Answer: e
mine :d--------------------------------------------------------------------------------
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
- were not formed early in the Moon’s history
- were not formed by the massive ejection of crustal debris
- are closely surrounded by other impact basins with anomalously low gravity
- were created by the impact of multiple large impactors
- were formed when the Moon was relatively elastic
Answer: a
mine e
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Q37:
Which of the following best describes the organization of the passage?
- An anomalous finding is cited, the data used to support that finding are analyzed, and the finding is modified.
- A theory about a phenomenon is introduced, data seeming to disprove that theory are analyzed, and the theory is rejected.
- A phenomenon is described, a finding relating to the phenomenon is discussed, and a possible explanation for that finding is offered.
- A debate among scientists regarding the explanation for a particular phenomenon is outlined, and one position in that debate is shown to be more persuasive.
- The observation of an astronomical event is described, and two schools of thought about the explanation for that event are discussed.
Answer: c
mine:b
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发表于 2005-11-20 19:54:00
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