Some trucks now run on cleaner burning diesel fuel engines, while others are using compressed or liquefied natural gas.

有些卡车已经使用清洁柴油引擎。其它一些卡车也有使用压缩或液化天然气燃料的。

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Buses emit more carbon than trains, but that can be minimized by using hybrid or compressed-natural-gas engines.

公车比火车排放的碳更多，但通过使用混合燃料车或压缩天然气引擎可以减少至最低。

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At present, except the small proportion of the pure natural gas engines, CNG vehicle powered device is basically flexible-fuel engine that can use natural gas or gasoline dividedly.

目前，我国的CNG汽车动力装置，除比例很小的纯天然气发动机之外，基本上是可以分别燃用天然气和汽油的两用燃料发动机。

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For gas prices to get this high on a sustained basis, you have to assume that either (a) shale gas will prove a colossal, over-hyped, mega-bust (something the Right is most definitely not in the usual business of positing) or (b) the U.S. auto-fleet will quickly transition to natural gas powered engines, driving up the demand for natural gas and, thus, the price.

FORBES: President Obama's Alleged "War On Coal" - Climate Change Edition