GWD4求助~~~~

Proposal:  Carbon dioxide and methane in the atmosphere block the escape of heat into space.  So emission of these “greenhouse” gases contributes to global warming.  In order to reduce global warming, emission of greenhouse gases needs to be reduced.  Therefore, the methane now emitted from open landfills should instead be burned to produce electricity.

Objection:  The burning of methane generates carbon dioxide that is released into the atmosphere.

Which of the following, if true, most adequately counters the objection made to the proposal?

A.      Every time a human being or other mammal exhales, there is some carbon dioxide released into the air.

B.       The conversion of methane to electricity would occur at a considerable distance from the landfills.

C.      The methane that is used to generate electricity would generally be used as a substitute for a fuel that does not produce any greenhouse gases when burned.

D.      Methane in the atmosphere is more effective in blocking the escape of heat from the Earth than is carbon dioxide.

E.       The amount of methane emitted from the landfills could be reduced if the materials whose decomposition produces methane were not discarded, but recycled.

为啥C不OK？~

Proposal结论是：应该燃烧M (而不是emitted from open landfills)来发电。

Objection 就说了，燃烧M会产生CO2, 照样会释放到大气中。

C 说用来发电的M一般可以用来做汽油的替代，其燃烧不会产生任何导致温室效应的气体。--- 这后半句很蹊跷，与题干的objection 矛盾。但这整句话的主题意思是仍是前半句，文中没有提到，我认为可以解释成无关选项。

D 说M在大气中比CO2更挡热，所以危害更大。---所以说，要燃烧M生产CO2,这样会减少挡热的作用，与Proposal观点一致。