大全-D-9，乱了乱了

In the industrialized nations, the last century has witnessed a shortening of the average workday from twelve hours or longer to less than eight hours. Mindful of this enormous increase in leisure time over the past century, many people assume that the same trend has obtained throughout history, and that, therefore, prehistoric humans must have labored incessantly for their very survival.

We cannot, of course, directly test this assumption. However, a study of primitive peoples of today suggests a different conclusion. The Mbuti of central Africa, for instance, spend only a few hours each day in hunting, gathering, and tending to other economic necessities. The rest of their time is spent as they choose. The implication is that the short workday is not peculiar to industrialized societies. Rather, both the extended workday of 1880 and the shorter workday of today are products of different stages of the continuing process of industrialization.

9. Which of the following inferences about industrialization is best supported by the passage above?

(A) People in advanced industrialized societies have more leisure time than those in nonindustrialized societies.

(B) An average workday of twelve hours or more is peculiar to economies in the early stages of industrialization.

(C) Industrialization involves a trade-off between tedious, monotonous jobs and the benefits of increased leisure.

(D) It is likely that the extended workday of an industrializing country will eventually be shortened.（D）

(E) As industrialization progresses, people tend to look for self-fulfillment in leisure rather than work.

这道题目为何选d，不是很清楚：

我从全文的理解感觉d正好是与原文的意思相反的阿/

原文：

上个世纪见证了工作时间的逐渐缩短，许多人认为相同的趋势会贯穿于人类历史。

However, a study of primitive peoples of today suggests a different conclusion. （不说明下面是不同的观点么？) 对原始民族的研究表明他们也花很少的时间工作，短的工作时间并非工业社会所特有的。1880年的长的工作时间和现在短的时间都是持续的工业化进程的不用阶段。

这样的结论并没有表明长的时间最重要被缩短阿，

或者是这样理解的？举了原始社会工作时间短的例子仅仅是为了驳斥第一部分说这个过程贯穿于人类历史，而工作时间的变化（长到短）仅仅存在于工业社会？？？？

nn能否帮忙把思路理一下？？我有点乱。。。谢谢！！！