注释：

1.. withdrawal of fresh water from rivers, lakes, reservoirs, and other sources has increased fourfold.……从江河、湖泊、水库和其他水源中减少的淡水量翻了四番。
2.the US Environmental Protection Agency (EPA)：美国环境保护局
3.... over 95 percent of urban sewage is discharged untreated...： 超过 95% 的城市污水未经处理就被排放(进）……本句中untreated是过去分词作状语，其逻辑主语就是句子的主语 over 95 percent of urban sewage。
4.The water body may then become choked with decaying algae. ?.：水域于是就有可倉旨被渐渐腐 烂的水藻所充塞……这里，become是系动词，过去分词choked作表语。
5.Erosion, the wearing away of topsoil by wind and rain, also contributes to water pollution.侵 蚀，也就是风雨对土壤表层的冲刷，也会带来水污染。contribute to...：对……起作用。
6.Even small amounts of silt can eliminate desirable fish species.甚至少量的游泥也可使一些宝 贵的鱼类灭种。
7.In 1992 there were 8,790 reported spills in and aroundUSwaters... ： 1992 年报道过在美国的 水域内以及水域周边有8，790起石油泄漏事件……

According to this passage, which of the following statements is true of yearly water consumption?

A:Most water is used for home cooking B:Most water is used for farming C:Cities use more water than rural areas D:America uses 8 percent of the world water resources

Water Pollution

    The demand for freshwater rises continuously as the world"s population grows. From 1940 to 1990，withdrawal of fresh water from rivers, lakes, reservoirs, and other sources has increased fourfold.¹ Of the water consumed each year, 69 percent is used for agriculture, 23 percent for industry, and 8 percent for domestic uses.

    Sewage, industrial wastes, and agricultural chemicals such as fertilizers and pesticides are the main causes of water pollution. In 1995，the US Environmental Protection Agency ( EPA)² reported that about 37 percent of the country"s lakes and estuaries, and 36 percent of its rivers, are too polluted for basic uses such as fishing or swimming, during all or part of the year. In developing nations，over 95 percent of urban sewage is discharged untreated³ into rivers and bays， creating a major human health hazard.

    Water runoff carries fertilizing chemicals such as phosphates and nitrates from agricultural fields and yards into lakes, streams, and rivers. These combine with the phosphates and nitrates from sewage to speed the growth of algae，a type of aquatic plant. The water body may then become choked with decaying algae,⁴ which severely depletes the oxygen supply. This process can cause the death of fish and other aquatic life. Runoff also carries toxic pesticides and urban and industrial wastes into lakes and streams.

    Erosion, the wearing away of topsoil by wind and rain, also contributes to water pollution.⁵ Soil and silt washed from logged hillsides，plowed fields，or construction sites，can clog waterways and kill aquatic vegetation. Even small amounts of silt can eliminate desirable fish species.⁶ For example，when logging removes the protective plant cover from hillsides，rain may wash soil and silt into streams, covering the gravel beds that trout or salmon use for spawning.

    The marine fisheries supported by ocean ecosystems are an essential source of protein,?

    particularly for people in developing countries ； approximately 950 million people worldwide consume fish as their primary source of protein. Yet pollution in coastal bays," estuaries, and wetlands threatens fish stocks already depleted by overfishing. In 1989 , 260,000 barrels of oil was spilled from the oil tanker Exxon Valdez into Alaska"sPrince William Sound, a pristine and rich fishing ground. In 1992 there were 8,790 reported spills in and around US waters,⁷ involving 5. 7 million liters (1.5 million gallons) of oil.

词汇：

sewage / ˈsu:ɪdʒ / n. 污水，污物 

fertilize  / "fɜ:təlaɪz / vt. 使肥沃，施肥于
erosion / ɪ"rəʊʒn / n. 腐蚀，侵蚀  

logging / ˈlɒgɪŋ / n. 伐木业
fertilizer / ˈfɜ:təlaɪzə(r)/ n. 肥料 

runoff / "rʌnˌɔ:f/ n.（地表）径流（量）
silt / sɪlt / n. 淤泥 

gravel / ˈgrævl / n. 砾石
phosphate / ˈfɒsfeɪt / n. 磷酸盐 

trout / traʊt / n. 鳟鱼
logged / lɔ:gd / adj. 被砍伐的 

nitrate /"naɪtreɪt / n. 硝酸盐
estuary /"estʃʊərɪ/ n. 河口湾，三角湾，港湾 

salmon / "sæmən / n. 大马哈鱼
clog / klɒg / v. 阻塞，填满 

alga / ˈældʒi / n. 水藻
bay / beɪ / n. 港湾 

spawn /spɔ:n / vt.    （鱼等）产卵
vegetation / ˌvedʒəˈteɪʃn/ n. 植被，植物 

aquatic /əˈkwætɪk / adj. 水生的，水产的
marine /mə"ri:n / adj. 海的，海上的 

toxic / ˈtɒksɪk / adj. 有毒的，有毒性的
deplete /dɪ"pli:t / vt. 耗尽，使空虚

pristine / ˈprɪsti:n / adj. 未受破坏的
ecosystem / ˈi:kəʊsɪstəm / n. 生态系统