57--61 DDCAD

　　57.主旨題。第一段后半部分引出主旨“They have trouble getting enough clean water for their basic needs.This situation may soon become common all around the world，...lack of clean water may be one of the biggest issues in the twenty-first century.”。第二段談及clean water變少的兩個主要原因，第三段告訴讀者既然可飲用水減少，人們就拼命掘井。然而井水也被污染。第四段說一旦地下水被污染，就不是短時間內可以恢復的。第五段闡述地下水污染的三個主要原因(化學物質、農業和廢物)。最后一段再次重申地下水問題的重要性并呼吁全球政府采取措施。因此，正確答案為D項。

　　58.細節推斷題。請看上下文“They have trouble getting enough clean water for their basic needs.This situation may soon become common all around the world，...lack of clean water may be one of the biggest issues in the twenty-first century”，由此可推斷將有越來越多的人喝不上、用不上干凈的水，故正確答案D項。

　　59.細節選擇題。第二段講干凈的水減少的原因“On the one hand，people are using more water than ever before...population of the world has more than doubled...On the other hand，many sources of surface water...--are too polluted and unhealthy for use as drinking water.”，即一方面人均用水量比以前增加，人口翻番;另一方面地表水污染嚴重，不適合飲用。因此正確答案為C項。

　　60.細節題。第三段中的“people in the United States began to find chemicals in their well water，...Weldon Spring，...，for example，..”說明美國科學家發現Weldon Spring這些地方的井水里有化學物質。因此正確答案為A項。

　　61.推斷題。倒數第二段“Industrial sites...are one cause of underground water pollution... Underground water pollution is also caused by modern farming methods，which require the use of large amounts of chemicals in the fields.And finally，yet another important cause of underground water pollution is waste”中清楚地說明了地下水污染的三大原因，即化學物質、農業化肥和廢棄物。因此正確答案為D項。