【考研类试卷】考研英语-955及答案解析.doc
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1、考研英语-955 及答案解析(总分:92.00,做题时间:90 分钟)一、Section Use of Eng(总题数:1,分数:10.00)Until about four decades ago, crop yields in agricultural systems depended on (1) resources, recycling organic matter, built-in biological control mechanisms and rainfall patterns. Agricultural yields were (2) but stable. Product
2、ion was (3) by growing more than one crop or variety in space and time in a field as insurance against pest (4) or severe weather. Inputs of nitrogen were (5) by rotating major field crops with legumes. In turn, rotations suppressed insects, weeds and diseases by effectively (6) the life cycles of t
3、hese pests. A typical corn belt farmer grew corn (7) with several crops including soybeans, and small grain production was intrinsic to maintain livestock. Most of the labor was done by the family with occasional hired help and no (8) equipment or services were purchased from off4arm sources. In the
4、se type of farming systems the link between agriculture and ecology was quite (9) and signs of environment degradation were seldom evident.But as agriculture modernization (10) the ecology-farming linkage was often broken as ecological principles were (11) . In fact, several agricultural scientists
5、have arrived at a (12) consensus that modem agriculture confronts an environment crisis. A growing number of people have become concerned about the long-term (13) of existing food production systems. Evidence has shown that (14) the present capital-and-technology-intensive fanning systems have been
6、extremely productive and competitive, they also bring a (15) of economic, environmental and social problems.Evidence also shows that the very nature of the agricultural structure and prevailing polices have led to this environmental (16) by favoring large farm size, specialized production, crop mono
7、cultures and mechanization. Today as more and more farmers are integrated (17) international economies, imperatives to (18) disappear and monocultures are rewarded by economies of scale. In turn, lack of rotations and diversification (19) key self-regulating mechanisms, turning monocultures into hig
8、hly (20) agro-ecosystems dependent on high chemical inputs.(分数:10.00)(1).A. external B. internal C. exported D. imported(分数:0.50)A.B.C.D.(2).A. small B. equivalent C. modest D. maximum(分数:0.50)A.B.C.D.(3).A. safeguarded B. ensured C. hindered D. disturbed(分数:0.50)A.B.C.D.(4).A. breakthrough B. outbu
9、rst C. sprawl D. outbreak(分数:0.50)A.B.C.D.(5).A. gained B. produced C. offered D. provided(分数:0.50)A.B.C.D.(6).A. recycling B. improving C. breaking D. repeating(分数:0.50)A.B.C.D.(7).A. integrated B. rotated C. combined D. cooperated(分数:0.50)A.B.C.D.(8).A. specific B. special C. specialized D. especi
10、al(分数:0.50)A.B.C.D.(9).A. weak B. compact C. remote D. strong(分数:0.50)A.B.C.D.(10).A. progressed B. processed C. provoked D. prolonged(分数:0.50)A.B.C.D.(11).A. followed B. applied C. ignored D. overestimated(分数:0.50)A.B.C.D.(12).A. general B. common C. unique D. usual(分数:0.50)A.B.C.D.(13).A. conserva
11、tion B. endurance C. progress D. sustainability(分数:0.50)A.B.C.D.(14).A. as B. whereas C. despite D. because(分数:0.50)A.B.C.D.(15).A. variety B. number C. quantity D. mixture(分数:0.50)A.B.C.D.(16).A. situation B. protection C. crisis D. issue(分数:0.50)A.B.C.D.(17).A. with B. to C. at D. into(分数:0.50)A.B
12、.C.D.(18).A. diversion B. diversity C. disease D. specialization(分数:0.50)A.B.C.D.(19).A. take away B. take in C. take off D. take up(分数:0.50)A.B.C.D.(20).A. efficient B. proficient C. intensive D. vulnerable(分数:0.50)A.B.C.D.二、Section Reading Co(总题数:0,分数:0.00)三、Part A(总题数:0,分数:0.00)四、Text 1(总题数:1,分数:
13、10.00)Nuclear fission is the splitting of the nucleus of an atom. Only a few elements are suitable for use in this way, the most important ones being Uranium-235, Uranium-233, and Plutonium-239. When a nucleus of one of these elements is struck by a free neutron it breaks down into two lighter nucle
14、i which fly apart at high speed, colliding with surrounding atoms. Their kinetic energy is converted into heat energy. At the same time, two or three free neutrons are released and one of them enters the nucleus of a neighbouring atom, causing fission to occur again; and so on. The reaction spreads
15、very quickly, with more and more heat energy released. This is called a “chain“ reaction because the splitting of each nucleus is linked to another, and another and another.If this reaction takes place in an atomic bomb, where nothing is done to slow it down, the result is a violent explosion that c
16、an destroy a town in a few seconds. Fission can also, however, take place within a construction called a nuclear reactor, or atomic pile. Here the highly fissile material (U-235, U-233, Pu-239) is surrounded by a substance that is non-fissile, for instance graphite. This material is called a moderat
17、or. The neutrons lose some of their energy and speed through colliding with the atoms of the moderator. Energyheat energyis still created on an enormous scale, but no expansion takes place. The moderator has another function: by slowing down the speed of the free neutrons, it makes it more likely th
18、at one of them will collide with the nucleus of a neighbouring atom to continue the chain reaction.The chief advantage of nuclear energy is that it does not depend on any local factors. A nuclear reactor, unlike an oil-well or a coalmine, does not have to be sited on top of a fossil-fuel source; unl
19、ike the solar energy unit, it does not have to go out of production when the sun is not shining; unlike hydro-electric power, it does not depend on a large flow of water which may be reduced during some seasons of the year. With an atomic power station, the only limiting factor is that of safety.In
20、the opposite process, nuclear fusion, two nuclei come together, to form a new nucleus of a different kind and this process also releases energy on an enormous scale. Fusion can only occur under conditions of very great heatat least 50000000 degrees Celsius. (The temperature at the centre of the sun
21、is estimated as 130000000 degrees Celsius.) A fusion reaction on earth has already been createdthe hydrogen bomb. This is an uncontrolled reaction. It is not yet possible to produce a controlled fusion reaction that can be used for the production of useful energy.Nuclear energy can be thought of as
22、a kind of square, Three of the quarters of the square are known and used, but the fourth cannot yet be used.(分数:10.00)(1).Which of the following headings is that of Paragraph Two?A. Nuclear FusionB. The Nuclear Fission Chain ReactionC. Uncontrolled and Moderated Nuclear ReactionsD. The Advantages of
23、 Nuclear Energy(分数:2.00)A.B.C.D.(2).The aim of a nuclear reactor is _.A. to establish a controlled chain reaction in low concentrations of fissile materialB. to absorb neutrons travelling at a particular speedC. to cause a rapid chain reaction in order to realease the greatest amount of energyD. to
24、last the chain reaction forever(分数:2.00)A.B.C.D.(3).Destructive weapons can be obtained from _.A. nuclear fusionB. nuclear fissionC. both nuclear fusion and nuclear fissionD. nuclear splitting(分数:2.00)A.B.C.D.(4).In nuclear fusion, two nuclei come together and _.A. form a new nucleusB. both splitC.
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- 考研 试卷 英语 955 答案 解析 DOC
