OG-11th 3

xxx_liuyi0206

请问OG11TH中CR的第三题，D选项OG给的解释是support，想来想去，不知为何，求达人指教：）

"Life expectancy" is the average age at death of the entire live-born population. In the middle of the nineteenth

century, life expectancy in North America was 40 years, wherreas now it is nearly 80 years. Thus, in those days,

people must have been considered old at an age that we now consider the prime of life.

Which of the following , if true, undermines the argument above?

A. In the middle of nineteenth century, the population of North America was significantly smaller than it is today.

B. Most of the gains in life expectancy in the last 150 years have come from reduction in the number of infants

who die in their first year life.

C. Many of the people who live to an advanced age today do so only because of medical technology that was

unknown in the nineteenth century.

D. The propotion of people who die in their seventies is significantly smaller today than is the proportiion of people

who die in their eighties.

E. More people in the middle of the nineteenth century engaged regularly in vigorous physical activity than do so

today.

先谢！

[此贴子已经被作者于2007-8-15 11:45:09编辑过]