18. Teresa: Manned spaceflight does not have a future, since it cannot compete economically with other means of accomplishing the objectives of spaceflight.
Edward: No mode of human transportation has a better record of reliability: two accidents in twenty-five years. Thus manned spaceflight definitely has a positive future.
Which of the following is the best logical evaluation of Edward’s argument as a response to Teresa’s argument?
(A) It cites evidence that, if true, tends to disprove the evidence cited by Teresa in drawing her conclusion.
(B) It indicates a logical gap in the support that Teresa offers for her conclusion.
(C) It raises a consideration that outweighs the argument Teresa makes.
(D) It does not meet Teresa’s point because it assumes that there is no serious impediment to transporting people into space, but this was the issue raised by Teresa.（D）
(E) It fails to respond to Teresa’s argument because it does not address the fundamental issue of whether space activities should have priority over other claims on the national budget.
19. Black Americans are, on the whole, about twice as likely as White Americans to develop high blood pressure. This likelihood also holds for westernized Black Africans when compared to White Africans.
Researchers have hypothesized that this predisposition in westernized Blacks may reflect an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt.
Which of the following statements about present-day, westernized Black Africans, if true, would most tend to confirm the researchers’ hypothesis?
(A) The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available, are low.
(B) The unusually high salt consumption in certain areas of Africa represents a serious health problem.
(C) Because of their blood pressure levels, most White Africans have markedly decreased their salt consumption.
(D) Blood pressures are low among the Yoruba, who, throughout their history, have been situated far inland from sources of sea salt and far south of Saharan salt mines.（A）
(E) No significant differences in salt metabolism have been found between those people who have had salt available throughout their history and those who have not.
请问18题的意思是什么？
19题的e为何不对？
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发表于 2004-6-23 22:59:00
