section5Questions30-35refer to the followingpassage.(1)When Pluto was first detected in1930，it was welcomed as a newly discovered planet.(2)Theirreaction was understandable.(3)Pluto was initially thought to be about thesize of Earth and therefore of proper planetary dimensions.(4)But by the late1970s，closerobservation had established that Pluto was in fact less than half the size ofMercury.(5)Dismayed，someastronomers now began to question whether so small an object deserved to beranked among the planets.(6)Pluto differs from the other planets also in that it is composedlargely of ice——more like a comet than a typical planet.(7)In the1990sit was discovered that Pluto was just the largest of hundreds of comet-likebodies occupying a region known as the Kuiper Belt. (8)Pluto，the doubters argued，should therefore be classedwith these icy objects rather than with the planets.(9)Rushing to Pluto’sdefense，manyastronomers rejected these arguments，pointingout that the established planets differ among themselves in both compositionand size.(10)Mars，forinstance，is composedof metal and rock，whileNeptune is mostly gas.(11)Why，then，could a planet not just aswell be composed of ice？(12)Andas for size difference，Jupiteris1300times larger than Earth，butno one would suggest that the two bodies therefore cannot both be planets.(13)Clearly they need to resolve the issue of Pluto’s classification.(14)In2006the International Astronomical Union defined a planet as a body that directlyorbits the Sun，islarge enough to be rounded by its own gravity，and has cleared its neighboring region of other orbitingbodies.(15)Pluto was judged to satisfy the first two criteria but not thethird，because of allthe Kuiper Belt objects populating its neighborhood.30.In context，which of the following is the best version of theunderlined portion of sentence1（reproducedbelow）？When Pluto was first detected in1930，it was welcomed as a newlydiscovered planet.(A)(asit is now)(B)itwas a newly discovered planet and welcomed as such(C)beinga newly discovered planet，itwas welcomed(D)thenewly discovered planet was also welcomed by astronomers(E)astronomerswelcomed it as a newly discovered planet答案：E解析：Sentence2的their指“一群人”，故Sentence1要出现“一群人”，只有E选项是astronomers正确。
ABC直接排除;D被动句，不简洁，且意思有所改变。
(C)Mercury，which was named for a Romanmessenger god(D)Mercury，which was discovered inancient times(E)Mercury，whose atmosphere is toothin to support human life答案：B解析：Sentence5：一些天文学家质疑Pluto太小，认为它不能算作行星。
Sentence4：Pluto 比Mercury的一半还小，此处添加的内容必须要凸显Pluto太小，与其他的planets的大小相差过大，从而与Sentence5相联系，与整段逻辑一致。
B：Mercury是traditional planets 中最小的，也就是说，Pluto与traditional planets的大小相差过大，符合题目要求。
其他选项属于无关选项。
32.Which of the following sentences，if inserted immediatelybefore sentence6，wouldprovide the most effective transition between the first and second paragraphs？(A)Pluto’s anomalous size was not theonly source of doubt.(B)Thiswas not the first time that a planet’sstatus has been called into question.(C)Suchscientific disputes can become surprisingly heated.(D)Thequestion of who deserves credit for a scientific discovery is sometimesdifficult to settle.(E)Manywere shocked at the suggestion that Pluto was not really a planet.答案：A解析：第一段的Sentence5提出Pluto受到质疑的一个原因：too small;第二段的Sentence 6提出第二个原因：composed of ice。
A：size不是唯一质疑，符合上下句;B、C与下文无关;D选项与上下文均无关。
此处已经提到了质疑的两方面，E选项中“Pluto有可能不是行星，这个说法让很多人震惊了”，与上下文的内容不符。
33.In context，which of the following is the best revision of theunderlined portion of sentence7(reproduced below)？In the1990s it was discovered thatPluto was just the largest of hundreds of comet-like bodies occupying a regionknown as the Kuiper Belt.(A)Inthe1990s，however，(B)Inthe1990s，bycomparison(C)Infact，in the1990s(D)Similarly，in the1990s(E)Consequently，in the1990s答案：C解析：Sentence6提出第二个质疑：composed of ice，Sentence7Pluto是许许多多的comet-like bodies中最大的，Sentence7更进一步说明Pluto与其他bodies相似，从而不能算作planets。
AB的转折关系错误;E的因果关系错误，原文没有“因此”这层意思，Sentence 7是事实，不是结论。
C的“In fact”符合题目要求。
D的similarly：同样地，Sentence7与Sentence6没有进行比较。
34.In context，which of the following is the best version of theunderlined portion of sentence13(reproduced below)?Clearly they need to resolve the issueof Pluto’sclassification.(A)(asit is now)(B)thepublic needs(C)somethingwas needed(D)furtherobservations were needed(E)aprecise definition of planet hood was needed答案：E解析：A选项中的的they无指代对象，且need时态错误;B的needs时态错误;C的something 表意不清;D、E相比，Sentence14提到了IAU对planet下的定义，所以从上下句看，E选项更符合要求。
35.Which of the following sentences,ifplaced immediately after sentence15,would best conclude the passage?(A)Pluto’s discover,Clyde Tombaugh,had died in1997and so did not live to see his beloved planet demoted.(B)Ceresand Pallas had undergone a similar demotion in the nineteenth century when theywere reclassified as asteroids rather than planets.(C)Ultimately,then,Pluto was demoted from planetary status not because of its small size butbecause of the clause company it keeps.(D)Thiswas perhaps the most momentous decision that the International AstronomicalUnion had made in its87-year history.(E)Nonetheless,supporters of Pluto point out that it has more moons than Mars,Earth, Venus,or Mercury.答案：C解析：总结句的作用有三个：一是重复前句，二是总结本段，三是总结全文。