GWD-TT-24的第一篇阅读（TTGWD11)不明白

snowhite1026

Q4~Q6: TTGWD11-Q35 to Q37:

          Citing the fact that the real gross domestic product(GDP) per capita was higher in 1997 than ever before, some journalists have argued that the United States economy performed ideally in 1997.  However, the real GDP is almost always higher than ever before; it falls only during recessions.  One point these journalists overlooked is that in 1997, as in the twenty-four years immediately preceding it, the real GDP per capita grew nearly one-half percent a year more slowly than it had on average between 1873 and 1973.  Were the 1997 economy as robust as claimed, the growth rate of real GDP per capita in 1997 would have surpassed the average growth rate of real GDP per capita between 1873 and 1973 because over fifty percent of the population worked for wages in 1997 whereas only forty percent worked for wages between 1873 and 1973.  If the growth rate of labor productivity (output per hour of goods and services) in 1997 had equaled its average growth rate between 1873 and 1973 of more than two percent, then, given the proportionately larger workforce that existed in 1997, real GDP per capita in 1997 would have been higher than it actually was, since output is a major factor in GDP. However, because labor productivity grew by only one percent in 1997, real GDP per capita grew more slowly in 1997 than it had on average between 1873 and 1973.

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Q5 -- Q36:   According to the passage, which of the following is true of the average rate at which real GDP per capita grew in the twenty-four years immediately before 1997?

A.      It was less than it had been between 1873 and 1973 because only forty percent of the population worked for wages between 1873 and 1973.

B.       It was less than it had been between 1873 and 1973 because labor productivity grew less between 1973 and 1997 than it had between 1873 and 1973.

C.      It was less than it had been between 1873 and 1973 as a result of an increase in the percentage of the population earning wages during these years.

D.      It was less than the average rate at which real GDP per capita grew between 1873 and 1973.

E.       It was less than the rate at which real GDP per capita grew in 1997.

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这个题不明白，虽然知道选D对，可是为什么不选B呢？最后一句不就是原因么？难道是因为B中讲的是1973-1997而原文是指1997么？

snowhite1026

大家都没有做这道么？还是我的问题太幼稚？