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问题 选择题

下列说法正确的是[ ]

A．Cl2和SO2的漂白原理不同，混合使用效果更好

B．测定等浓度的CH3COONa和NaCN溶液的pH分别为8.8和11.1，可以判断反应CH3COOH+NaCN→CH3COONa+HCN不能发生

C．溶液中滴加盐酸酸化的BaCl2溶液出现白色沉淀，则溶液中一定存在SO42-

D．若通入Cl2后，溶液变为黄色，加入淀粉溶液后变蓝色，可确定溶液中含有I-

答案

答案：D

填空题

单词拼写。

1. He was interested in a _____ and always stayed up at  night to watch the stars.

2. Computer hackers have broken down security s ____,  raising questions about the safety

    of information.

3. There is a lot of rubbish ____(漂浮)on the surface of the river.

4. W _____(当心 )out! There is a car coming!

5. Every time an English runner won a race, the crowd c  ____  .
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问答题 简答题

怎样安装和拆出接地线？
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