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问题 填空题

含有较多可溶性______化合物的水叫硬水，不含或含较少______的水叫软水．区别硬水和软水的试剂是______，现象是______．生活中可以通过______的方法降低水的硬度．

答案

含有较多可溶性钙镁离子化合物的水是硬水；鉴别软水和硬水用肥皂水，泡沫多的是软水，泡沫少的是硬水．硬水在煮沸时会产生水垢．

故答案为：钙镁；可溶性钙、镁化合物；用肥皂水；加入肥皂水搅拌，泡沫多、浮渣少的是软水；煮沸

多项选择题

规划的环境影响分析与评价的方法包括（）。

A.情景分析法

B.费用效益分析法

C.层次分析法

D.对比评价法
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单项选择题

Questions 58 to 62 are based on the following passage: ( 10分)　　According to the airline industry statistics, almost 90% of airline accidents are survivable or partially survivable. But passengers can increase their chances of survival by learning and following certain tips. Experts say that you should read and listen to safety instructions before takeoff and ask questions if you have uncertainties. You should fasten your seat belt low on your hips as tightly as possible. Of course, you should also know how the release mechanism of your belt operates. During takeoffs and landings you are advised to keep your feet flat on the floor. Before takeoff you should locate the nearest exit and an alternative exit and count the rows of seats between you and the exits so that you can find them in the dark if necessary.　　In the event that you are forewarned of a possible accident, you should put your hands on your ankles and keep your head down until the plane comes to a complete stop. If smoke is present in the cabin, you should keep your head low and cover your face with napkins, towels, or clothing. If possible, wet these for added protection against smoke inhalation. To evacuate as quickly as possible, follow crew commands and do not take personal belongings with you. Do not jump on escape slides before they are fully inflated, and when you jump, do so with your arms and legs extended in front of you. When you get to the ground, you should move away from the plane as quickly as possible, and never smoke near the wreckage.

According to the passage, people have more chances to survive fires in aircraft if they __

A．keep their feet flat on the floor

B．keep their heads low

C．fasten their seat belts tightly

D．read airline safety statistics before takeoff
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