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[语文] 新GRE阅读理解36套每日讨论--46(群178674184)

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发表于 2011-10-23 09:00:15 | 显示全部楼层 |阅读模式
If a supernova (the explosion of a massive star) trig-
gered star formation from dense clouds of gas and dust,
and if the most massive star to be formed from the cloud
evolved into a supernova and triggered a new round of
star formation, and so on, then a chain of star-forming
regions would result. If many such chains were created
in a differentially rotating galaxy, the distribution of
stars would resemble the observed distribute in a
spiral galaxy.
This line of reasoning underlies an exciting new
theory of spiral-galaxy structure. A computer simulation
based on this theory has reproduced the appearance of
many spiral galaxies without assuming an underlying
density wave, the hallmark of the most widely accepted
theory of the large-scale structure of spiral galaxies.
That theory maintains that a density wave of spiral
form sweeps through the central plane of a galaxy,
compressing clouds of gas and dust, which collapse
into stars that form a spiral pattern.


(160 words)




7. The primary purpose of the passage is to
(A) describe what results when a supernova triggers
the creation of chains of star-forming regions
(B) propose a modification in the most widely
accepted theory of spiral-galaxy structure
(C) compare and contrast the roles of clouds of gas
and dust in two theories of spiral-galaxy
structure
(D) describe a new theory of spiral-galaxy structure
and contrast it with the most widely accepted
theory
(E) describe a new theory of spiral-galaxy structure
and discuss a reason why it is inferior to the
most widely accepted theory


8. The passage implies that, according to the new
theory of spiral-galaxy structure, a spiral galaxy can
be created by supernovas when the supernovas are
(A) producing an underlying density wave
(B) affected by a density wave of spiral form
(C) distributed in a spiral pattern
(D) located in the central plane of a galaxy
(E) located in a differentially rotating galaxy


9. Which of the following, if true, would most
discredit the new theory as described in the passage?
(A)The exact mechanism by which a star becomes
a supernova is not yet completely known
and may even differ for different stars.
(B) Chains of star-forming regions like those
postulated in the new theory have been
observed in the vicinity of dense clouds of
gas and dust.
(C) The most massive stars formed from supernova
explosions are unlikely to evolve into super-
novas.
(D) Computer simulations of supernovas provide a
poor picture of what occurs just before a
supernova explosion.
(E) A density wave cannot compress clouds of gas
and dust to a density high enough to create a
star.
发表于 2011-10-23 10:21:05 | 显示全部楼层
D,E,C
 楼主| 发表于 2011-10-24 08:14:24 | 显示全部楼层
楼上答对了!!

大家多点人来做啊,这周大家加油!
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