Material 4-6Text AWe sometimes think humans are uniquely vulnerable to anxiety, but stress seems to affect the immune defenses of lower animals too. In one experiment, for example, behavioral immunologist Mark Laudenslager, at the University of Denver, gave mild electric shocks to 24 rats. Half the animals could switch off the current by turning a wheel in their enclosure, while the other half could not. The rats in the two groups were paired so that each time one rat turned the wheel it protected both itself and its helpless partner from the shock. Laudenslager found that the immune response was depressed below normal in the helpless rats but not in those that could turn off the electricity. What he has demonstrated, he believes, is that lack of control over an event, not the experience itself, is what weakens the immune system.Other researchers agree. Jay Weiss, a psychologist at Duke University School of Medicine, has shown that animals who are allowed to control unpleasant stimuli don't develop sleep disturbances or changes in brain chemistry typical of stressed rats. But if the animals are confronted with situations they have no control over, they later behave passively when faced with experiences they can control. Such findings reinforce psychologists' suspicions that the experience or perception of helplessness is one of the most harmful factors in depression.One of the most startling examples of how the mind can alter the immune response was discovered by chance. In 1975 psychologist Robert Ader at the University of Rochester School of Medicine conditioned mice to avoid saccharin by simultaneously feeding them the sweetener and injecting them with a drug that while suppressing their immune systems caused stomach upsets. Associating the saccharin with the stomach pains, the mice quickly learned to avoid the sweetener. In order to extinguish this dislike for the sweetener, Ader re-exposed the animals to saccharin, this time without the drug, and was astonished to find that those mice that had received the highest amounts of sweetener during their earlier conditioning died. He could only speculate that he had so successfully conditioned the rats that saccharin alone now served to weaken their immune systems enough to kill them.1. Laudenslager's experiment showed that the immune system of those rats who could turn off the electricity .A. was strengthenedB. was not affectedC. was alteredD. was weakened2. The reason why the mice in Ader's experiments avoided saccharin was that .A. they disliked its tasteB. it affected their immune systemsC. it led to the passive reaction in controllable situationsD. they rendered the pain inside body.3. The passage tells us that the most probable reason for the death of the mice in Ader's experiment was that .A. they had been weakened psychologically by the saccharinB. the sweetener was poisonous to themC. their immune systems had been altered by the mindD. they had taken too much sweetener during earlier conditioning4. It can be concluded from the passage that the immune systems of animal ^ .A. can be weakened by conditioningB. can be suppressed by drug injectionsC. can be affected by frequent doses of saccharinD. can be altered by electric shocksText BComputer programmers often remark that computing machines, with a perfect lack of discrimination, will do any foolish thing they are told to do. The reason for this lies, of course, in the narrow fixation of the computing machine's "intelligence" on the details of its own perceptions—its inability to be guided by any large context. In a psychological description of the computer intelligence, three related adjectives come to mind: single-minded, literal-minded, and simple-minded. Recognizing this, we should at the same time recognize that this single-mindedness, literal-mindedness, and simple-mindedness also characterizes theoretical mathematics, though to a lesser extent.Since science tries to deal with reality, even the most precise sciences normally work with more or less imperfectly understood approximations toward which scientists must maintain an appropriate skepticism. Thus, for instance, it may come as a shock to mathematicians to learn that the Schrodinger equation for the hydrogen atom is not a literally correct description of this atom, but only an approximation to a somewhat more correct equation taking account of spin, magnetic dipole, and relativistic effects; and that this corrected equation is itself only an imperfect approximation to an infinite set of quantum field—theoretical equations.Physicists, looking at the original Schrodinger equation, learn to sense in it the presence of many invisible terms in addition to the differential terms visible, and this sense inspires an entirely appropriate disregard for the purely technical features of the equation. This very healthy skepticism is foreign to the mathematical approach. Mathematics must deal with well-defined situations. Thus, mathematicians depend on an intellectual effort outside of mathematics for the crucial specification of the approximation that mathematics is to take literally. Give mathematicians a situation that is the least bit ill-defined, and they will make it well-defined, perhaps appropriately, but perhaps inappropriately.In some eases, the mathematicians' literal-mindedness may have unfortunate consequences. The mathematicians turn the scientists' theoretical assumptions, that is, their convenient points of analytical emphasis, into axioms, and then take these axioms literally. This brings the danger that they may also persuade the scientists to take these axioms literally. The question, central to the scientific investigation but intensely disturbing in the mathematical context—what happens if the axioms are relaxed? —is thereby ignored. The physicist rightly dreads precise argument, since an argument that is convincing only if it is precise loses all its force if the assumptions on which it is based are slightly changed, whereas an argument that is convincing though imprecise may well be stable under small perturbations of its underlying assumptions.5. The author discusses computing machines in the first paragraph primarily in order to________.A. indicate the dangers inherent in relying to a great extent on machinesB. illustrate his views about the approach of mathematicians to problem solvingC. compare the work of mathematicians with that of computer programmersD. provide one definition of intelligence6. According to the passage, scientists are skeptical toward their equations because scientistsA. work to explain real, rather than theoretical or simplified situationsB. know that well-defined problems are often the most difficult to solveC. are unable to express their data in terms of multiple variablesD. are unwilling to relax the axioms they have developed7. According to the passage, mathematicians present a danger to scientists because _____.A. mathematicians may provide theories that are incompatible with those already developed by scientistsB. mathematicians may define situation in a way that is incomprehensible to scientistsC. mathematicians may convince scientists that theoretical assumptions are factsD. scientists may come to believe that axiomatic statements are untrue8. According to the author, how is the approach of physicists to solving scientific problems?A. Practical for scientific purposes.B. Detrimental to scientific progress.C. Unimportant in most situations.D. Expedient, but of little long-term value.9. The author suggests that a mathematician asked to solve a problem in an ill-defined situation would first at tempt to_____.A. identify an analogous situationB. simplify and define the situationC. vary the underlying assumptions of a description of the situationD. determine what use would be made of the solution provided10. The author implies that scientists develop a healthy skepticism because they are aware that_____.A. mathematicians are better able to solve problems than scientistsB. changes in axiomatic propositions will inevitably undermine scientific argumentsC. well-defined situations are necessary for the design of reliable experimentsD. some factors in most situations must remain unknown。