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2011-09-09 16:22:00 来源：网络整理 双击单词自动翻译
作文地带导读：SECTION Ⅱ Time-35 minutes 24 Questions Directions: The questions in this section are based on the reasoning contained in brief statements or passages For some questions more than one of the choices could conceivably answer th
Questions 3-4
Although water in deep aquifers does not contain disease-causing bacteria, when public water supplies are arawn from deep aquifers chlorine is often added to the water as a disinfectant because contamination can occur as a result of flaws in pipes or storage tanks. Of 50 municipalities that all pumped water from the same deep aquifer 30 chlorinated their water and 20 did not. The water in all of the municipalities met the regional government's standards for cleanliness yet the water supplied by the 20 municipalities that did not chlorinated had less bacterial contamination than the water supplied by the municipalities that added chlorine.
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