大全－11－15

大全sec11－15

The level  of lead contamination in United States rivers declined between 1975 and 1985. Federal legulation requiring a drop  in industrial discharges of lead went into effect in 1975, but the major cause of  the decline was a 75 percent  drop in the use of leaded gasoline between 1975 and 1985.

Which of the following, if true, best supports the claim that the major cause of the decline in the level  of lead contamination in United States river was the decline in the use of leaded gasoline?

A The level of lead contamination in United States rivers fell sharply in both 1975 and 1983

B Most of the decline in industrial discharges of lead occurred before 1976, but the largest decline in the level of river contamnation occured between 1980 and 1985

C Level of lead contamination in river fell sharply in 1975-1976 and rose very slightly over the next nine years.

D Level of lead contamination rose in those rivers where there was reduced river flow due to drought

E Although the use of leaded gasoline declined 75 percent between 1975 and 1985,80 percent of the decline took place in 1985.

ans:B

but I think B can eliminate that the decline of lead contamination is not due to the requirement but can not include that the main clause is the decline use of leaded gasoline.

thanks

可以解释一下吗

B Most of the decline in industrial discharges of lead occurred before 1976, but the largest decline in the level of river contamnation occured between 1980 and 1985

the sentence tells us that the drop of lead contamination is neither due to the decline in industrial discharges nor the regulation of the government.

大全sec11－15

The level  of lead contamination in United States rivers declined between 1975 and 1985. Federal legulation requiring a drop  in industrial discharges of lead went into effect in 1975, but the major cause of  the decline was a 75 percent  drop in the use of leaded gasoline between 1975 and 1985.

Which of the following, if true, best supports the claim that the major cause of the decline in the level  of lead contamination in United States river was the decline in the use of leaded gasoline?

A The level of lead contamination in United States rivers fell sharply in both 1975 and 1983

B Most of the decline in industrial discharges of lead occurred before 1976, but the largest decline in the level of river contamnation occured between 1980 and 1985

C Level of lead contamination in river fell sharply in 1975-1976 and rose very slightly over the next nine years.

D Level of lead contamination rose in those rivers where there was reduced river flow due to drought

E Although the use of leaded gasoline declined 75 percent between 1975 and 1985,80 percent of the decline took place in 1985.

ans:B

the between 1980 and 1985 -- 排除了和 FED relegisltaion 有關

但這題僦是用排除法來做

~open to discuss, help us on this question,~

不知道这题是不是真这么想？

感觉像是诡辩逻辑。

希望知道该题出自何处，是笔试还是jj?

或是以前的模拟题？

B committed an obvious logic flaw. X causes Y does not equate to Very X can cause Very Y. For example, strong men are attractive, so very strong men are very attractive. This reasoning is flawed.  

The conclusion states that the drop in the use of leaded gasoline causes decline in the level of lead contamination in rivers. B assumes that the most of the decline in the use of leaded gasoline should cause the largest decline in the level of river contamination. It committed same logic flaw as the example above. However, all other choices are so wrong that B is the only answer left. That's the reason for the question to say "best support". We just need to pick the best answer, not the perfect answer, out of the 5 choices.  I, too, question the authenticity and accuracy of 大全.