2. The prices are dropping quickly, back to below three dollars a gallon in many areas. 价格下降的非常快，在很多地方又回到一加仑三美元以下。
3. Keeping your tires inflated properly can improve gas mileage by more than 3%. Every gallon of gasoline saved keeps 20 pounds of carbon dioxide out of the atmosphere! 保持轮胎充气能令每单位燃料的行驶哩数增加超过3%。而每节省一加仑汽油，大气中的二氧化碳就能减少20磅。
英英解释
n.
1. United States liquid unit equal to 4 quarts or 3.785 liters
2. a British imperial capacity measure (liquid or dry) equal to 4 quarts or 4.545 liters
