The recent debate on acid rain is again setting environmentalist head to head against industry. But this time, a curious philosophy has emerged in Washington that says the more we know about a problem, the more uncertainty is introduced and the more it needs to be studied. As a result, we know more about acid rain and its effects, than ever before, but it seems a regulatory solution has never been further away.Researchers generally agree that acid rain arises primarily from the burning of coal and oil. The emissions contain oxides of nitrogen and sulfur, which can be carried hundreds of miles on the prevailing westerly winds. They eventually return to earth as dry gases and particulates and react with ground waters to form nitric or sulfuric acid. They may also be converted to the acids in the atmosphere by chemical processes that are still not fully understood.However, the acids are formed, they have already been charged with a substantial list of damages. Corrosion of metal structures in windward areas of the country has been well- documented, but it is a relatively minor entry on the list. Other forms of damage are far more insidious and longer-lasting. There is evidence, for example, that the acids leach heavy metals —aluminum, lead, and mercury — from the soil, which then poison plant roots and deprive them of vital nutrients. In lakes and rivers, the acid alters the blood chemistry in fish. The metals, meanwhile, irreversibly damage the gill systems of certain species, such as bass and walleye. As the concentration of poison rises, egg hatching is reduced and the number of deformed embryos increases.The effects of acid rain are more severe in the eastern part of the country for two reasons. First, most coal burning occurs in Ohio, Illinois, and Indiana, according to Eville Gorham, professor of ecology and botany at the University of Minnesota and a modern pioneer in the study of acid rain. These states produce about a quarter of all U.S. oxide emissions, he told this year’s American Chemical Society meeting in Las Vegas and the airborne particulates tend to wind up in the Northeast.The second reason is the varying chemical makeup of North American soils, Western soils are relatively rich in neutralizing compounds like magnesium and calcium carbonates, but the coarse, shallow eastern soils have much less of this buffering capacity. Together, these factors explain what Gorham calls a “pool of acid air pollution” over the Northeast that is strongly suspected of having killed or injured aquatic life in more than 200 lakes in New York’s Adirondack region.1.According to the passage, acid rain （ ）.2.The author implies that （ ）.3.The damaging effects of acid rain are felt less in the West because （ ）.4.The LEAST serious problem caused by acid rain is the（ ）.

A.leads to birth defects in fish B.is hallucinogenic C.travels in a westerly direction D.adds minerals to the soil
问题2：
A.legislators are philosophical B.bureaucrats seemingly prefer discussion to action C.awareness of a problem is futile D.acid rain is a debatable phenomenon
问题3：
A.elements in western soil neutralize the acid B.the western states produce one-fourth of all American emissions of sulfur oxides C.the Adirondack region is in upstate New York D.eastern soil is rich in magnesium
问题4：
A.leaching of heavy metals from the soil B.alteration of blood chemistry in fish C.poisoning of plant roots D.corrosion of metal structures