新GRE阅读机经：Supernova.

　　下面是小编为大家整理的新GRE机经的阅读部分，这篇是关于“Supernova”的新GRE阅读机经，希望可以帮助各位考生打开阅读思路，提高新GRE阅读能力。

　　获得更多留学知识 请咨询澳际免费在线顾问

　　Supernova

　　Astronomers observe a supernova that is dimmer than expected because of dust screening，If a supernova (the explosion of a massive star) triggered 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.

　　16.1. 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 23

　　16.2. 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

　　16.3. 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 supernovas.

　　(D) Computer simulations of supernovas provide a poor picture of what occurs just bore a supernova explosion.

　　(E) A density wave cannot compress clouds of gas and dust to a density high enough to create a star.

　　答案：DEC

　　以上就是关于Supernova的新GRE阅读机经，希望能够帮助各位考生更好地备考新GRE。机经的作用是非常重要的，有很多机经会反复考到，大家可以进行认真阅读，从中推断出出题人的出题思路，总结出新GRE阅读的解题，做到杀G成功!