og12 1

Kath1985

1."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, whereas 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 the 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 reductions in the
number of infants who die in their first year

of 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 proportion of people who die in their
seventies is significantly smaller today than is the
proportion 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.
答案B
沒查到有人討論這題 想請問為什麼是B? 能不能用數字舉例....
感激

darlingchum

假如有一群人4个吧
两个0岁死了两个活到80 平均年龄是40

on the other hand
如果他们都活80岁 平均年龄还是80岁

无论在哪种情况下80岁的都是老人

前者即使平均年龄是40岁 40岁也只是中年

所以说平均年龄的降低有可能是出生死亡率高引起的