Theworld’sastronomerscametothe...阅读答案

The world’s astronomers came to their senses yesterday and approved a new definition of the word “planet” that would drop tiny Pluto from the club and relegate it instead to a lesser realm of “dwarf planets.” It was a welcome step away from a proposal that would have kept Pluto as a planet but meantime opened the door for dozens of small, icy bodies on the fringes of the solar system. The important vote came after fierce debate at a meeting of the International Astronomical Union, which had been considering a proposal to define a planet as any object that orbits a star and is large enough for its own gravity to pull it into a spherical (球形的) shape. That definition was scientifically precise but led to results that offended common sense. An asteroid, a small moon, and another icy ball like Pluto would suddenly have risen to planet-hood, swelling the number of planets to 12, with many more icy rocks likely to qualify as more was learned about them. Fortunately, the astronomers have now added another requirement to the definition. Planets must not only be large enough to be round, they must also have cleared out the neighborhood around their orbits. Pluto would not qualify — it orbits in a belt of icy debris on the edge of the solar system. Neither would an icy rock nicknamed Xena, which orbits in that same zone, nor Ceres, a big asteroid that marches in the company of other asteroids. Pluto’s moon, Charon, which had qualified under the first proposal, is also out of the running. Pluto, with its small size and oddball orbit, should never have been deemed a planet in the first place. Henceforth there will be eight planets, at least three dwarf planets, and tens of thousands of “smaller solar system bodies,” like comets and asteroids. Our only regret is that the astronomers chose the name “dwarf planets” for Pluto’s new category instead of abandoning the word entirely when discussing these less-than-planetary bodies. 46. We can know from the passage that the new definition of planet __________. A. has been welcomed by all walks of life B. will kick the Pluto out of the planet group in the solar system C. still makes the Pluto as a planet D. will enlarge the number of planets in our solar system into permanently 12 47. After the new definition of “planet” was put forward, all of the following are regarded as planet except________. A. Venus B. Ceres C. Mars D. Jupiter 48. The writer’s attitudes towards the new definition of “planet” is________. A. welcome B. indifferent C. hostile D. neutral 49 If the original definition of “planet” had not been changed, there would be the following consequences except that ________. A. thousands of icy rocks in space will be classified as planets B. some asteroids big enough to pull itself into a spherical shape will be regarded as planets. C. the Pluto will be relegated to “dwarf planet” D. there will be at least twelve or even more planets in the solar system. 50. We can infer from the article that the decision to apply new definition to “planet”________. A. has won universal support from scientists. B. has been severely criticized by many astronomers C. has not been made inconsiderately. D. has been banned by the International Astronomical Union

46.Ｂ 47.Ｂ 48.Ａ 49.Ｃ 50.Ｃ 解析: 46. 细节理解题。本文主要探讨天文学家如何定义planet，新的规定已将太阳系的行星Pluto去掉，从九颗降为八颗，而避免了升为12颗。由首段that would drop tiny Pluto from the club and relegate it instead to a lesser realm of “dwarf planets.”可得出正确答案。 47. 细节理解题。由第三段倒数第二句可知，Ceres只是asteroid，而不是planet，其他几个都在存留的八颗行星当中。 48. 推理判断题。最后一段“Pluto, with its small size and oddball orbit, should never have been deemed a planet in the first place”, 表明作者对这一决定是拥护的。 49. 细节理解题。如果”planet” 的定义不改变，Pluto不会降级，将仍为planet，可见选项C错。由首段 “opened the door for dozens of small, icy bodies on the fringes of the solar system.”可知，也提到其他太空体也将成为planet，可见在这种假设下A、B和D项都成立。 50. 推理判断题。由第二段首句The important vote came after fierce debate at a meeting可知。

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