小伙伴们，GRE考试大家复习的怎么样了呢？下面是帮考网分享的一些GRE考试阅读部分的复习资料，一起来看看吧！

释义部分：

1

Although, recent years have seen substantial reductions in noxious pollutants from individual motor vehicles, the number of such vehicles has been steadily increasing, consequently, more than 100 cities in the United States still have levels of carbon monoxide, particulate matter, and ozone (generated by photochemical reactions with hydrocarbons from vehicle exhaust) that exceed legally established limits.

尽管近年来单体机动车的有害排放物显著降低，但机动车总数一直稳步增加，结果是，美国超过 100 座城市的一氧化碳，有害悬浮颗粒，臭氧(机动车尾气与碳氢化合物发生光化学反应的产物)水平超过法定标准。

2

There is a growing realization that the only effective way to achieve further reductions in vehicle emissions — short of a massive shift away from the private automobile — is to replace conventional diesel fuel and gasoline with cleaner-burning fuels such as compressed natural gas, liquefied petroleum gas, ethanol, or methanol.

越来越多人相信唯一有效的减排方案 —— 除了私家车大规模减少 —— 就是用更清洁的燃料替换传统柴油和汽油，比如压缩天然气，液化石油气，乙醇，或甲醇。

(short of 此处为介词，除了，除非，other than)

3

All of these alternatives are carbon-based fuels whose molecules are smaller and simpler than those of gasoline.

这些替代燃料与汽油同属碳基燃料，但分子更小更简单。

4

These molecules burn more cleanly than gasoline, in part because they have fewer, if any, carbon-carbon bonds, and the hydrocarbons they do emit are less likely to generate ozone.

这些分子比汽油燃烧更干净，某种程度上是因为它们含有更少的，如果有的话，碳碳键，且它们释放的碳氢化合物更不易产生臭氧。

5

The combustion of larger molecules, which have multiple carbon-carbon bonds, involves a more complex series of reactions.

6

These reactions increase the probability of incomplete combustion and are more likely to release uncombusted and photochemically active hydrocarbon compounds into the atmosphere.

这些反应增加了不充分燃烧的可能性，也更可能向大气中释放未氧化且具有光化学反应活性的碳氢化合物。

7

On the other hand, alternative fuels do have drawbacks.

另一方面，替代燃料也有劣势。

8

Compressed natural gas would require that vehicles have a set of heavy fuel tanks — a serious liability in terms of performance and fuel efficiency — and liquefied petroleum gas faces fundamental limits on supply.

压缩天然气需要车辆加装一组沉重的油箱 —— 难以实施也影响效率 —— 而液化石油气面临严重的供给限制。

9

Ethanol and methanol, on the other hand, have important advantages over other carbon based alternative fuels: they have a higher energy content per volume and would require minimal changes in the existing network for distributing motor fuel.

乙醇和甲醇，另一方面，相对于其他碳基替代燃料有重要优势：单位体积所产生的能量更高，且对现有配给网络秩序做出最小改动。

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