1、考博英语模拟试卷 161及答案与解析 一、 Reading Comprehension 0 The antigen-antibody immunological reaction used to be regarded as typical of immunological responses. Antibodies are proteins synthesized by specialized cells called plasma cells, which are funned by lymphocytes (cells from the lymph system when an anti
2、gen, a substance foreign to the organisms body, comes in contact with lymphocytes. Two important manifestations of antigen- antibody immunity are lysis, the rapid physical rupture of antigenic cells and the liberation of their contents into the surrounding medium, and phagocytosis, a process in whic
3、h antigenic particles are engulfed by and very often digested by macrophages and polymorphs. The process of lysis is executed by a complex and unstable blood constituent known as complement, which will not work unless it is activated by a specific antibody; the process of pbagocytosis is greatly fac
4、ilitated when the particles to be engulfed are coated by a specific antibody directed against them. The reluctance to abandon this hypothesis, however well it explains specific processes, impeded new research, and for many years antigens and antibodies dominated the thoughts of immunologists so comp
5、letely that those immunologists overlooked certain difficulties. Perhaps the primary difficulty with the antigen-antibody explanation is the informational problem of how an antigen is recognized and how a structure exactly complementary to it is then synthesized. When molecular biologists discovered
6、, moreover, that such information cannot flow from protein to protein, hut only from nucleic acid to protein, the theory that an antigen itself provided the mold that directed the synthesis of an antibody had to be seriously qualified. The attempts at qualification and the information provided by re
7、search in molecular biology led scientists to realize that a second immunological reaction is mediated through the lymphocytes that are hostile to and bring about the destruction of the antigen. This type of immunological response is called cell- mediated immunity. Recent research in cell-mediated i
8、mmunity has been concerned not only with the development of new and better vaccines, but also with the problem of transplanting tissues and organs from one organism to another, for although circulating antibodies play a part in the rejection of transplanted tissues, the primary role is played by cel
9、l-mediated reactions. During cell-mediated responses, receptor sites on specific lymphoeytes and surface antigens on the foreign tissue cells form a complex that binds the lymphocytes to the tissue. Such lymphocytes do not give rise to antibody- producing plasma cells but themselves bring about the
10、death of the foreign-tissue cells, probably by secreting a variety of substances, some of which are toxic to the tissue cells and some of which stimulate increased phagocyte activity by white blood cells of the macrophage type. Cell-mediated immunity also accounts for the destruction of intracellula
11、r parasites. 1 The passage suggests that scientists might not have developed the theory of cell-mediated immunological reactions if_. （ A） proteins existed in specific group types （ B） proteins could have been shown to direct the synthesis of other proteins （ C） antigens were always destroyed by pro
12、teins （ D） antibodies were composed only of protein 2 The author argues that the antigen-antibody explanation of immunity “had to be seriously qualified“ because_. （ A） antibodies were found to activate unstable components in the blood （ B） antigens are not exactly complementary to antibodies （ C） l
13、ymphocytes have the ability to bind to the surface of antigens （ D） antibodies are synthesized from protein whereas antigens are made from nucleic acid 3 The author most probably believes that the antigen-antibody theory of immunological reaction_. （ A） is wrong （ B） was accepted without evidence （
14、C） is unverifiable （ D） is a partial explanation 4 The author mentions all of the following as being involved in antigen-antibody immunological reactions EXCEPT the_. （ A） synthesis of a protein （ B） activation of complement in the bloodstream （ C） destruction of antibodies （ D） entrapment of antige
15、ns by macrophages 5 The author supports the theory of cell-mediated reactions primarily by _. （ A） pointing out a contradiction in the assumption leading to the antigen-antibody theory （ B） explaining how cell mediation accounts for phenomena that the antigen-antibody theory cannot account for （ C）
16、revealing new data that scientists arguing for the antigen-antibody theory have continued to ignore （ D） showing that the antigen-antibody theory fails to account for the breakup of antigens 5 Since the dawn of human ingenuity, people have devised ever more cunning tools to cope with work that is da
17、ngerous, boring, burdensome, or just plain nasty. That compulsion has resulted in roboticsthe science of conferring various human capabilities on machines. And ff scientists have yet to create the mechanical version of science fiction, they have begun to come close. As a result, the modern world is
18、increasingly populated by intelligent gizmos whose presence we barely notice but whose universal existence has removed much human labor. Our factories hum to the rhythm of robot assembly arms. Our banking is done at automated teller terminals that thank us with mechanical politeness for the transact
19、ion. Our subway trains are controlled by tireless robot-drivers. And thanks to the continual miniaturization of electronics and micro-mechanics, there are already robot systems that can perform some kinds of brain and bone surgery with submillimeter accuracyfar greater precision than highly skilled
20、physicians can achieve with their hands alone. But if robots are to reach the next stage of laborsaving utility, they will have to operate with less human supervision and be able to make at least a few decisions for themselvesgoals that pose a real challenge. “While we know how to tell a robot to ha
21、ndle a specific error,“ says Dave Lavery, manager of a robotics program at NASA, “we cant yet give a robot enough common sense to reliably interact with a dynamic world.“ Indeed the quest for true artificial intelligence has produced very mixed results. Despite a spell of initial optimism in the 196
22、0s and 1970s when it appeared that transistor circuits and microprocessors might be able to copy the action of the human brain by the year 2010, researchers lately have begun to extend that forecast by decades if not centuries. What they found, in attempting to model thought, is that the human brain
23、s roughly one hundred billion nerve cells are much more talentedand human perception far more complicatedthan previously imagined. They have built robots that can recognize the error of a machine panel by a fraction of a millimeter in a controlled factory environment. But the human mind can glimpse
24、a rapidly changing scene and immediately disregard the 98 percent that is irrelevant, instantaneously focusing on the monkey at the side of a winding forest road or the single suspicious face in a big crowd. The most advanced computer systems on the earth cant approach that kind of ability, and neur
25、oscientists still dont know quite how we do it. 6 Human ingenuity was initially demonstrated in _. （ A） the use of machines to produce science fiction （ B） the wide use of machines in manufacturing industry （ C） the invention of tools for difficult and dangerous work （ D） the elites cunning tackling
26、 of dangerous and boring work 7 The word “gizmos“ (Line 1, Paragraph 2) most probably means _. （ A） programs （ B） experts （ C） devices （ D） creatures 8 According to the passage, what is beyond mans ability now is to design a robot that can_. （ A） fulfill delicate tasks like performing brain surgery
27、（ B） interact with human beings verbally （ C） have a little common sense （ D） respond independently to a changing world 9 Besides reducing human labor, robots can also _. （ A） make a few decisions for themselves （ B） deal with some errors with human intervention （ C） improve factory environments （ D
28、） cultivate human creativity 10 The author uses the example of a monkey to argue that robots are _. （ A） expected to copy human brain in internal structure （ B） able to perceive abnormalities immediately （ C） far less able than human brain in focusing on relevant information （ D） best used in a cont
29、rolled environment 10 About twice every century, one of the massive stars in our galaxy blows itself apart in a supernova explosion that sends massive quantities of radiation and matter into space and generates shock waves that sweep through the arms (a narrow extension of a larger area, mass, or gr
30、oup) of the galaxy. The shock waves heat the interstellar gas, evaporate small clouds, and compress larger ones to the point at which they collapse under their own gravity to form new stars. The general picture that has been developed for the supernova explosion and its aftermath goes something like
31、 this. Throughout its evolution, a star is much like a leaky balloon. It keeps its equilibrium figure through a balance of internal pressure against the tendency to collapse under its own weight. The pressure is generated by nuclear reactions in the core of the star which must continually supply ene
32、rgy to balance the energy that leaks out in the form of radiation. Eventually the nuclear fuel is exhausted, and the pressure drops in the core. With nothing to hold it up, the matter in the center of the star collapses inward, creating higher and higher densities and temperatures, until the nuclei
33、and electrons are fused into a super-dense lump of matter known as a neutron star. As the overlying layers rain down on the surface of the neutron star, the temperature rises, until with a blinding flash of radiation, the collapse is reversed. A thermonuclear shock wave runs through the now expandin
34、g stellar envelope, fusing lighter elements into heavier ones and producing a brilliant visual outburst that can be as intense as the light of 10 billion suns. The shell of matter thrown off by the explosion plows through the surrounding gas, producing an expanding bubble of hot gas, with gas temper
35、atures in the millions of degrees. This gas will emit most of its energy at X-ray wavelengths, so it is not surprising that X-ray observatories have provided some of the most useful insights into the nature of the supernova phenomenon. More than twenty supernova remnants have now been detected in X-
36、ray studies. Recent discoveries of meteorites with anomalous concentrations of certain isotopes indicate that a supernova might have precipitated the birth of our solar system more than four and a half billion years ago, Although the cloud that collapsed to form the sun and the planets was composed
37、primarily of hydrogen and helium, it also contained carbon, nitrogen, and oxygen, elements essential for life as we know it. Elements heavier than helium are manufactured deep in the interior of stars and would, for the most part, remain there if it were not for the cataclysmic supernova explosions
38、that blow giant stars apart. Additionally, supernovas produce clouds of high- energy particles called cosmic rays. These high-energy particles continually bombard the earth and are responsible for many of the genetic mutations that are the driving force of the evolution of species. 11 Which of the f
39、ollowing titles best describes the content of the passage? （ A） The Origins and Effects of Supernovas. （ B） The Life and Death of Stars. （ C） The Origins and Evolution of Life on the Earth. （ D） The Aftermath of a Supernova. 12 According to the passage, we can expect a supernova to occur in our gala
40、xy _. （ A） about twice each year （ B） hundreds of times each century （ C） about once every fifty years （ D） about once every other century 13 According to the passage a neutron star is _. （ A） a gaseous cloud containing heavy elements （ B） an intermediate stage between an ordinary star and a superno
41、va （ C） the residue that is left by a supernova （ D） the core of an ordinary star that houses the thermonuclear reactions 14 Which of the following methods does the author employ to develop the first paragraph? （ A） Analogy. （ B） Deduction. （ C） Generalization. （ D） Example. 15 The author implies th
42、at _. （ A） it is sometimes easier to detect supernovas by observation of the X-ray spectrum than by observation of visible wavelengths of light （ B） life on the earth is endangered by its constant exposure to radiation forces that are released by a supernova （ C） recently discovered meteorites indic
43、ate that the earth and other planets of our solar system survived the explosion of a supernova several billion years ago （ D） lighter elements are formed from heavier elements during a supernova as the heavier elements are torn apart 15 The uniqueness of the Japanese character is the result of two s
44、eemingly contradictory forces: the strength of traditions and selective receptivity to foreign achievements and inventions. As early as the 1860s, there were counter movements to the traditional orientation. Yukichi Fukuzawa, the most eloquent spokesman of Japans “Enlightenment“, claimed: “The Confu
45、cian civilization of the East seems to me to lack two things possessed by Western civilization: science in the material sphere and a sense of independence in the spiritual sphere.“ Fukuzawas great influence is found in the free and individualistic philosophy of the Education Code of 1872, but he was
46、 not able to prevent the government from turning back to the canons of Confucian thought in the Imperial Rescript of 1890. Another interlude of relative liberalism followed World War I, when the democratic idealism of President Woodrow Wilson had an important impact on Japanese intellectuals and, es
47、pecially students; but more important was the Leninist ideology of the 1917 Bolshevik Revolution. Again in the early 1930s, nationalism and militarism became dominant, largely as a result of failing economic conditions. Following the end of World War II, substantial changes were undertaken in Japan
48、to liberate the individual from authoritarian restraints. The new democratic value system was accepted by many teachers, students, intellectuals, and old liberals, but it was not immediately embraced by the society as a whole. Japanese traditions were dominated by group values, and notions of person
49、al freedom and individual rights were unfamiliar. Today, democratic processes are clearly evident in the widespread participation of the Japanese people in social and political life; yet, there is no universally accepted and stable value system. Values are constantly modified by strong infusions of Western ideas, both democratic and Marxist. School textbooks expound democratic principles, emphasizing equality over hierarchy and rationalism over tradition; but in practice these values arc often misinterpr
