GRE阅读真题之OG2 Passage 20.

上海新东方网GRE频道在此和大家分享GRE官方指南中的阅读真题，希望对大家准备GRE阅读有所帮助。

OG-2

Passage 20

The nearly circular orbits of planets in our solar system led scientists to expect that planets around other stars would also reside in circular orbits. However, most known extrasolar planets reside in highly elongated, not circular, orbits. Why? The best clue comes from comets in our solar system. Comets formed in circular orbits but were gravitationally flung into their present-day elliptical orbits when they ventured too close to planets. Astronomers suspect that pairs of planets also engage in this slingshot activity, leaving them in disturbed, elliptical orbits. If two planets form in close orbits, one will be scattered inward (toward its star), the other outward. They will likely then travel close enough to neighboring planets to disturb their orbits also.

For the following question, consider each of the choices separately and select all that apply.

1. According to the passage, which of the following factors help account for the elliptical shape of the orbits of extrasolar planets?

A. The planets’ formation in close proximity to other planets

B. The gravitational influence of planets whose original orbits have been disturbed

C. The gravitational influence of comets

For the following question, consider each of the choices separately and select all that apply.

2. The passage suggests that two planets formed in close orbits that engaged in “slingshot activity” (lines 10-11) would be likely to

A. deflect away from each other

B. change the shape of each other’s orbit

C. affect the orbits of any neighboring planets

点击查看答案

推荐阅读

【汇总】2017年托福听力备考

【汇总】2017年托福阅读备考

【汇总】2017年托福写作备考

【汇总】2017年托福口语备考

上海新东方英语班报名地址
托福	雅思	GRE	GMAT	SAT
基础班	IELTS 5.5分班	基础班	强化班	基础班
强化班	IELTS 6.5分班	强化班		强化班
精讲精练班	IELTS 7分班	精讲精练班	精讲精练班	精讲精练班
点题班	雅思词汇班	模考班	模考班	模考班
更多	更多	更多	更多	更多