下列变化中，发生化学变化的是( )
A．干冰升华
B．石油分馏
C．氧气的工业制法
D．钢铁生锈
答案：D
A、干冰升华的过程中没有新物质生成，只是发生了状态变化，属于物理变化，故A错误；
B、石油分馏是根据沸点不同加以分离，过程中没有生成新物质，属于物理变化，故B错误；
C、氧气的工业制法是利用了氧气和氮气的沸点不同，过程中没有新物质生成，属于物理变化，故C错误；
D、钢铁生锈的过程中有铁锈生成，属于化学变化，故D正确；
故选D．
Passage Two
| Cars account for half the oil consumed in the U.S. , about half the urban pollution and one fourth the greenhouse gases. They take a similar toll (损耗) of resources in other industrial nations and in the cities of the developing world．As vehicle use continues to increase in the coming decade, the U.S. and other countries will have to deal with these issues or else face unacceptable economic, health-related and political costs. It is unlikely that oil prices will remain at their cur- rent low level or that other nations will accept a large and growing U. S. contribution to global climatic change. Policymakers and industry have four options: reduce vehicle use, increase the efficiency and reduce the emissions of conventional gasoline-powered vehicles, switch to less harmful fuels, or find less polluting driving systems. The last of these—in particular, the introduction of vehicles powered by electricity-is ultimately the only sustainable (可持续的) option The other alternatives are attractive in theory but in practice are either impractical or offer only marginal improvements. For example, reduced vehicle use could solve traffic problems and a host of social and environmental problems, but evidence from around the world suggests that it is very difficult to make people give up their cars to any significant extent. In the U.S. mass-transit rider ship and carpooling (合伙用车) have declined since World War Ⅱ. Even in western Europe, with fuel prices averaging more than＄1 a liter (about ＄ 4 a gallon) and with easily accessible mass transit and dense populations, cars still account for 80 percent of all passenger travel. Improved energy efficiency is also appealing, but automotive fuel economy has barely made any progress in 10 years. Alternative fuels such as natural gas, burned in internal-combustion engines, could be introduced at relatively low cost, but they would lead to only marginal (边缘的最低限度的) reductions in pollution and greenhouse emissions (especially because oil companies are already spending billions of dollars every year to develop less polluting types of gasoline). |
Which of the following statements is true according to the passage
A．The decline of public transportation accounts for increased car use in western Europe.
B．Cars are popular in western Europe even though fuel prices are fairly high.
C．The reduction of vehicle use is the only sustainable option in densely populated western Europe.
D．Western European oil companies cannot sustain the cost of developing new-type fuels.