Question

All too often , a choice that seems sustainable（可持續(xù)的）turns out on closer examination to be problematic. Probably the best example is the rush to produce ethanol（乙醇）for fuel from corn . Corn is a renewable resource —you can harvest it and grow more, almost limitlessly. So replacing gas with corn ethanol seems like a great idea.

One might get a bit more energy out of the ethanol than that used to make it, which could still make ethanol more sustainable than gas generally, but that’s not the end of the problem. Using corn to make ethanol means less corn is left to feed animals and people, which drives up the cost of food. That result leads to turning the fallow land — including, in some cases, rain forest in places such as Brazil — into farmland, which in turn gives off lots of carbon dioxide（CO2）into the air. Finally, over many years, the energy benefit from burning ethanol would make up for the forest loss. But by then, climate change would have progressed so far that it might not help.

You cannot really declare any practice “sustainable” until you have done a complete lift-cycle analysis of its environmental（環(huán)境的）costs. Even then, technology and public policy keep developing, and that development can lead to unforeseen and undesired results. The admirable goal of living sustainable requires plenty of thought on an ongoing basis.

What might directly cause the loss of the forest according to the text?

A. The growing demand for energy to make ethanol.

B. The increasing carbon dioxide in the air.

C. The greater need for farmland.

D. The big change in weather.

The underline word “it” in the second paragraph refers to

A. the energy benefit               B. the forest loss

C. climate change                  D. burning ethanol

The author thinks that replacing gas with corn ethanol is    

A. impractical   B. acceptable    C. admirable    D. useless

What does the author mainly discuss in the text?

A. Technology.                   B. Sustainability.

C. Ethanol energy.               D. Environmental protection.

Answer 1

【小題1】C

【小題2】A

【小題3】A

【小題4】B

解析:

【小題1】推理判斷題。注意問的是直接原因。That result leads to turning the fallow land — including, in some cases, rain forest in places such as Brazil — into farmland.

【小題2】根據(jù)上下文可知是指能源優(yōu)勢。

【小題3】作者意圖判斷題。根據(jù)全文可知作者認為用corn代替gas是不符合實際的，會帶來很多意想不到的問題。

【小題4】主旨判斷題。讀完全文我們可以知道，作者主要談?wù)摰氖强沙掷m(xù)性的判斷依據(jù)以及相關(guān)一些事實。該題容易誤選D。