阅读理解Alltooftenachoicethatseemssustainable(可持续的)turnsoutoncloserexaminationtobeproblematic．Probablythebestexampleistherushtoproduceethanol(乙醇)forf

Question

阅读理解

　　All to often a choice that seems sustainable( 可持续的 )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 resouree － 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 ethand 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 carbon dioxide(CO ₂ )into the air ． Finally over many years the energy benefit from buring 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 life-cycle analysis of its environmental( 环境的 )costs ． Even then technology and public policy keep developing and that development can lead to unforeseen and undesired results ． The admirable goal of living sustainably requires plenty of thought on an ongoing basis ．

(1)

What might directly cause the loss of the forest according to the text?
[　　]
A．	The growing demand for energy to make ethaol ．
B．	The increasing carbon dioxide in the air ．
C．	The greater need for farmland ．
D．	The big change in weather ．

(2)

The underlined word “ it ” in the second paragraph refers to “ ________ ”．
[　　]
A．	the energy benefit
B．	the forest loss
C．	climate change
D．	burning ethanol

(3)

The author thinks that replacing gas with corn ethanol is ________ ．
[　　]
A．	impractical
B．	acceptable
C．	admirable
D．	useless

(4)

What does the author mainly discuss in the text?
[　　]
A．	Technology ．
B．	Sustainability ．
C．	Ethanol energy ．
D．	Environmental protection ．

Answer 1

答案：1．C;2．A;3．A;4．B;