28. The text suggests which of the following about air pollution? [A] Further attempts to reduce emissions from gasoline-fueled vehicles will not help lower urban       air-pollution levels. [B] Attempts to reduce the pollutants that an individual gasoline-fueled vehicle emits have been largely unsuccessful. [C] Few serious attempts have been made to reduce the amount of pollutants emitted by gasoline-fueled vehicles. [D] Pollutants emitted by gasoline-fueled vehicles are not the most critical source of urban air   pollution。

　　29. Which of the following most closely parallels the situation described in the first sentence of the text? [A] Although a town reduces its public services in order to avoid a tax increase, the town’s tax rate exceeds that of other towns in the surrounding area. [B] Although a state passes strict laws to limit the type of toxic material that can be disposed of in public landfills, illegal dumping continues to increase. [C] Although a town’s citizens reduce their individual use of water, the town’s water supplies continue to dwindle because of a steady increase in the total populating of the town. [D] Although a country attempts to increase the sale of domestic goods by adding a tax to the price of imported goods, the sale of imported goods within the country continues to increase。

　　30. It can be inferred that the author of the text most likely regards the criticism of methanol as       [A] flawed because of the assumptions on which it is based. [B] inapplicable because of an inconsistency in the critics’ arguments. [C] misguided because of its exclusively technological focus. [D] inaccurate because it ignores consumers’ concerns。

　　Text 3

　　The use of heat pumps has been held back largely by skepticism about advertisers’ claims that heat pumps can provide as many as two units of thermal energy for each unit of electrical energy used, thus apparently contradicting the principle of energy conservation。

　　Heat pumps circulate a fluid refrigerant that cycles alternatively from its liquid phase to its vapor phase in a closed loop. The refrigerant, starting as a low-temperature, low-pressure vapor, enters a compressor driven by an electric motor. The refrigerant leaves the compressor as a hot, dense vapor and flows through a heat exchanger called the condenser, which transfers heat from the refrigerant to a body of air. Now the refrigerant, as a high-pressure, cooled liquid, confronts a flow restriction which causes the pressure to drop. As the pressure falls, the refrigerant expands and partially vaporizes, becoming chilled. It then passes through a second heat exchanger, the evaporator, which transfers heat from the air to the refrigerant, reducing the temperature of this second body of air. Of the two heat exchangers, one is located inside, and the other one outside the house, so each is in contact with a different body of air: room air and outside air, respectively。