Bracken, a poisonous weed, is spreading and damaging much pastureland in the Northern Hemisphere. One potentially inexpensive and self-sustaining countermeasure is to introduce natural enemies of the plant; therefore, some scientists have proposed to control bracken by a release of brackeneating moths native to the Southern Hemisphere into brackeninfested areas in the Northern Hemisphere. If the scientists’ proposal for controlling bracken is adopted, which of the following is a necessary condition for its success
A. That bracken in the Northern Hemisphere grows in approximately the same climates and soil conditions in which it grows in the Southern Hemisphere.
B. That the released moths will feed on weeds other than bracken that are native to the Northern Hemisphere.
C. That the livestock that will return to pastures now lost to bracken will develop immunities to the diseases caused by bracken.
D. That the released moths will survive in sufficient numbers to build a population large enough to reduce bracken and retard its growth.
E. That traditional methods of control, such as burning, cutting, and chemical spraying, will not become less expensive or labor-intensive than they are now.
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(91～93题共用题干)男性，60岁，肺气肿史，发热咳嗽一周，痰量多而黏稠，胸片右上肺大片状阴影内有多个空腔，水平裂呈向下弧形 患者出血原因最可能是
A. 食管胃底静脉曲张破裂
B. 胃溃疡出血
C. 脾破裂
D. 脾功能亢进
Although the ratio of physicians to total population is about the same in the United States and Canada, the United States has 33 percent more surgeons per capita. Clearly, this is the reason people in the United States undergo 40 percent more operations per capita than do Canadians. The explanation given above rests on an assumption that
A. patients in the United States do not have a greater need for surgery than do patients in Canada.
B. the population of the United States is not larger than that of Canada.
C. United States patients sometimes travel to Canada for certain kinds of surgery.
D. general practitioners in the United States do not as a role examine a patient who is a candidate for surgery before sending the patient to a surgeon.
E. there are no unnecessary surgical operations performed in Canada.
In March 300 college students turned out in Washington to protest against proposed cuts in student loan funds. Another 350,000 collegians flocked to Florida’s sun-drenched beaches during March for "spring break." Since the Florida sun-seekers were more numerous, they were more representative of today’s students than those who protested in Washington, and therefore Congress need not heed the appeals of the protesting students. The argument above makes which of the following assumptions
A. The students who vacationed in Florida did not oppose the cutting of student loan funds by Congress.
B. The students who vacationed in Florida were not in agreement with the opinion of the majority of United States citizens about the proposed cut in loan funds.
C. The students who protested in Washington were more seriously concerned about their education than were the students who vacationed in Florida.
D. The students who neither protested in Washington in March nor vacationed in Florida in March are indifferent to governmental policies on education.
E. The best way to influence congressional opinion about a political issue is to communicate with one’s elected representative in Washington.
Armtech, a temporary-employment agency, previously gave its employees 2. 5 paid vacation days after each 700 hours worked. Armtech’s new policy is to give its employees 5.0 paid vacation days after each 1,200 hours worked. Therefore, this new policy is more generous to Armtech employees in giving them more vacation days per hour worked than the old policy did. Which of the following is an assumption on which the argument depends
A. Most current Armtech employees approve of the company’s new vacation policy.
B. A few Armtech employees leave the company before having worked 700 hours.
C. Most Armtech employees were not aware that the company planned to change its vacation policy until after it had already done so.
D. A significant portion of Armtech employees stay with the company long enough to work for 1,200 hours.
E. Armtech’s new vacation policy closely matches the vacation policies of competing temporary employment agencies.
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