【考研类试卷】考研英语-试卷49及答案解析.doc
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1、考研英语-试卷 49 及答案解析(总分:142.00,做题时间:90 分钟)一、Use of English(总题数:2,分数:80.00)1.Section I Use of EnglishDirections: Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D.(分数:40.00)_Many teachers believe that the responsibilities for learning lie with the student. (1)
2、_ a long reading assignment is given, instructors expect students to be familiar with the (2)_ in the reading even if they do not discuss it in class or take an examination. The (3)_ student is considered to be (4)_ who is motivated to learn for the sake of (5)_, not the one interested only in getti
3、ng high grades. Sometimes homework is returned (6)_ brief written comments. but without a grade. Even if a grade is not given, the student is (7)_ for learning the material assigned. When research is (8)_, the professor expects the student to take it actively and to complete it with (9)_ guidance. I
4、t is the (10)_ responsibility to find books, magazines, and articles in the library. Professors do not have the time to explain (11)_ a university library works; they expect students, (12)_ graduate students, to be able to exhaust the reference (13)_ in the library. Professor will help students who
5、need it, but (14)_ that their students should not be (15)_ dependent on them. In the United States professors have many other duties (16)_ teaching, such as administrative or research work. (17)_, the time that a professor can spend with a student outside of class is (18)_. If a student has problems
6、 with classroom work, the student should either (19)_ a professor during office hours (20)_ make an appointment.(分数:40.00)A.IfB.AlthoughC.BecauseD.SinceA.suggestionB.contextC.abstractD.informationA.poorB.idealC.averageD.disappointedA.suchB.oneC.anyD.someA.funB.workC.learningD.prizeA.byB.inC.forD.wit
7、hA.criticizedB.innocentC.responsibleD.dismissedA.collectedB.distributedC.assignedD.finishedA.maximumB.minimumC.possibleD.practicalA.student“sB.professor“sC.assistant“sD.librarian“sA.whenB.whatC.whyD.howA.particularlyB.essentiallyC.obviouslyD.rarelyA.selectionsB.collectionsC.sourcesD.originsA.hateB.d
8、islikeC.likeD.preferA.tooB.suchC.muchD.moreA.butB.exceptC.withD.besidesA.HoweverB.ThereforeC.FurthermoreD.NeverthelessA.plentifulB.limitedC.irregularD.flexibleA.greetB.annoyC.approachD.attachA.orB.andC.toD.but二、Reading Comprehensio(总题数:10,分数:58.00)2.Section II Reading Comprehension_3.Part ADirection
9、s: Read the following four texts. Answer the questions below each text by choosing A, B, C or D._The origin of continental nuclei has long been a puzzle. Theories advanced so far have generally failed to explain the first step in continent growth, or have been subject to serious objections. It is th
10、e purpose of this article to examine the possible role of the impact of large meteorites or asteroids in the production of continental nuclei. Unfortunately, the geological evolution of the Earth“s surface has had an obliterating effect on the original composition and structure of the continents to
11、such an extent that further terrestrial investigations have small chance of arriving at an unambiguous answer to the question of continental origin. Paradoxically, clues to the origin and early history of the surface features of the Earth may be found on the Moon and planets, rather than on the Eart
12、h, because some of these bodies appear to have had a much less active geological history. As a result, relatively primitive surface features are preserved for study and analysis. In the case of both the Moon and Mars, it is generally concluded from the appearance of their heavily cratered surfaces t
13、hat they have been subjected to bombardment by large meteoroids during their geological history. Likewise, it would appear a reasonable hypothesis that the Earth has also been subjected to meteoroid bombardment in the past, and that very large bodies struck the Earth early in its geological history.
14、 The largest crater on the Moon listed by Baldwin has a diameter of 285 km. However, if we accept the hypothesis of formation of some of the mare basins by impact, the maximum lunar impact crater diameter is probably as large as 650 km. Based on a lunar analogy, one might expect several impact crate
15、rs of at least 500 km diameter to have been formed on Earth. By applying Baldwin“s equation, the depth of such a crater should be about 20 km. Baldwin admits that his equation gives excessive depths for large craters so that the actual depth should be somewhat smaller. Based on the measured depth of
16、 smaller lunar craters, a depth of 10 km is probably a conservative estimate for the diameter of a 500 km impact crater. Baldwin“s equation gives the depth of the zone of brecciation for such a crater as about 75 km. The plasticity, of the Earth“s mantle at the depth makes it impossible to speak of
17、“brecciation“ in the usual sense. However, local stresses may be temporarily sustained at that depth, as shown by the existence of deep-focus earthquakes. Thus, short-term effects might be expected to a depth of more than 50 km in the mantle. Even without knowing the precise effects, there is little
18、 doubt that the formation of a 500 km crater would be a major geological event. Numerous authors have considered the geological implications of such an event. Donn et al. have, for example, called on the impact of continent-size bodies of sialic composition to form the original continents. Two major
19、 difficulties inherent in this concept are the lack of any known sialic meteorites, and the high probability that the energy of impact would result in a wide dissemination of sialic material, rather than its concentration at the point of impact. Gilvarry, on the other hand, called on meteoroid impac
20、t to explain the production of ocean basins. The major difficulties with this model are that the morphology of most of the ocean basins is not consistent with impact, and that the origin and growth, of continents is not adequately explained. We agree with Donn et al. that the impact of large meteori
21、tes or asteroids may have caused continent formation, but would rather think in terms of the localized addition of energy to the system, rather than in terms of the addition of actual sialic material.(分数:10.00)(1).A mare basin is_.(分数:2.00)A.a formula for determining the relationship between the dep
22、th and width of cratersB.a valley that is filled in when a spatial body has impact with the moon or the earthC.a planetoid(small planet)created when a meteorite, upon striking the moon, breaks off a Part of the moonD.a dark spot on the moon, once supposed to be a sea, now a plain(2).The writer does
23、not believe that_.(分数:2.00)A.an asteroid is larger than a meteoriteB.material from space, upon hitting the earth, was eventually distributedC.the earth, at one time, had cratersD.oceans were formerly craters(3).The passage is primarily concerned with_.(分数:2.00)A.the origin of continentsB.the relatio
24、nship between astral phenomena and the moonC.differences of opinion among authoritative geologistsD.the relationship between asteroids and meteorites(4).Sialic material refers to_.(分数:2.00)A.the broken,rock resulting from the impact of a meteorite against the earthB.material that exists on planets o
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- 考研 试卷 英语 49 答案 解析 DOC