[求助]01.5阅读答案有问题呀！

likui

      Factories also offered a reprieve from the backbreaking work and financial

      unpredictability associated with farming. Many adults, poor and disillusioned with

      farm life, were lured to the cities by promises of steady employment, regular paychecks,

      20)  increased access to goods and services, and expanded social portunities.   Others         w   were

      pushed there when new technologies made their labor cheap or expendable; inventions

      such as steel plows and mechanized harvesters allowed one farmhand to perform work

      that previously had required several, thus making farming capital-intensive rather than

      labor-intensive.

7.The word “expendable” in line 21 is closest in

  meaning to

  (A) nonproductive

  (B) unacceptable

  (C) nonessential

  (D) unprofitable

参考答案说是 D ～不可能呀！！

Others （many adults）were pushed there (the cities) when new technologies made their labor cheap or expendable

另外一些成年人被迫迁往大城市，当新科技使得他们劳力廉价，并非不可缺少。

这里是科技使的劳力不是那么非必须的意思吗，怎么是 unprofitable 无收益的意思呢？

应该选 C 呀！！

再者，见朗文～

expendable   adjective  

not needed enough to be kept or saved

- It's a sad moment when a man loses his job and discovers that he is expendable.  

The inference that some types of sedimentary rocks are the result of glacial activity

    is based on the principle of uniformitarianism, which posits that natural processes now

10)  at work on and within the Earth operated in the same manner in the distant past.

44. It can be inferred from the passage that the principle of uniformitarianism indicates that

  (A) similar conditions produce similar rock formations

  (B) rock layers in a given region remain undisturbed over time

  (C) different kinds of sedimentary rocks may

(D) each continent has its own distinctive pattern of sediment layers

答案说是 C ～

C 是什么意思的说，好像没有打全是怎么的～

我看应该是 A 吗！