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问题 选择题

下列化学用语使用正确的是[ ]

A．Cl-的结构示意图：

B．乙酸的结构式为：

C．乙烯的结构简式：CH2CH2

D．HCO3-水解的离子方程式：HCO3- + H2OH3O+ +CO32-

答案

答案：B

改错题

文中共有10处语言错误，每句中最多有两处，每处错误仅涉及一个单词的增加、删除或修改。

注意：1. 每处错误及其修改均仅限一词； 

2. 只允许修改10处，多者（从第11处起）不计分。

Yang Li, a five-year-old girl living next door to me, very clever. Because she is not old enough to go to the school, she often asks me to teach herself to read, write and draw. She studies hardly and soon she learns a lot. One evening last month I was doing my English homeworks when she came to my house. She asked me how I learned English. “You would find English a bridge for so much knowledge,” I said. She then wanted to learn English, either. She has learned many English words so far but her parents are very grateful to me.

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单项选择题

通过直线的平面方程为（）。

A．x-z-2=0

B．x+z=0

C．x-2y+z=0

D．x+y+z=1
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