????7. 液化或壓縮天然氣

????使用液化或壓縮天然氣的天然氣汽車的續(xù)航里程和汽油車相仿，但燃燒更清潔。美國環(huán)保部（the Energy Department）估計，目前全美在用天然氣汽車共有112,000輛。它們大多數(shù)是中型或重型卡車，但本田汽車（Honda）1998年就已經(jīng)推出了天然氣版的思域（Civic）。它比汽油版速度慢，行駛里程有限，加注網(wǎng)絡也不完善，同時還要貴上好幾千美元。有利于它推廣的地方在于，這種燃料更便宜，在國內生產(chǎn)，排放也更低。

????7. Liquefied and compressed natural gas

????Natural gas vehicles, operating on either liquefied or compressed gas, produce mileage similar to gasoline but burn more cleanly. The Energy Department estimates that some 112,000 vehicles powered by natural gas are currently in operation. Most are medium and heavy-duty trucks, but Honda (HMC) has offered a natural gas Civic (above) since 1998. It is slower than a gasoline one, has a limited range and refueling network, and costs thousands of dollars more. In its favor are cheaper prices for a fuel that is produced domestically and lower emissions.