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问题 单项选择题

以十八烷基硅烷键合硅胶(ODS)为固定相、乙腈一水为流动相进行液相色谱分离的方法是( )。

A．离子抑制色谱法

B．离子对色谱法

C．反相色谱法

D．正相色谱法

E．吸附色谱法

答案

参考答案：C

解析：[知识点] 高效液相色谱法

问答题 简答题

为什么油烧着了不能用水去泼？
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单项选择题

Americans use more water than any other people in the world. If we continue to use water at the rate we do now, we will soon not have enough to meet our needs. In 1980, 40 billion gallons were used each day in the United States. In 1990, 700 billion gallons were used. The average Americans uses almost 90 gallons of water a day for personal use. And much move water is needed to make the things American people like to have. For example, it takes thousands of gallons of water to make one pound of beef for the dinner table. It takes more than 100,000 gallons of water to make a car. If we include these uses of water, the average American uses about 2000 gallons of water a day.

Americans used ______ gallons of water each day in 1980.

A．40 billion

B．90 billion

C．700 billion

D．200 billion
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