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问题 选择题

下列离子方程式正确的是（   ）

A．将氯气通入氯化亚铁溶液：2Fe2++Cl2=2Fe3++2Cl－

B．钠与水的反应：Na+2H2O=Na++2OH－+H2↑

C．铜片跟稀硝酸的反应：Cu+NO3－+4H+=Cu2++NO↑+2H2O

D．金属铝溶于氢氧化钠溶液：Al+2OH－=AlO2－+H2↑

答案

答案：A

A 对

B错 电荷不守恒

C 错 电荷不守恒

D 错 电荷不守恒，应有水参加反应

填空题

根据短文内容及首字母提示，完成下列单词拼写。

     I have a g   1    friend in my school. Her n   2    is Li Ying. She gets up early every day. She likes to b   3    early. She does morning exercises a   4    she gets up at six. Then she washes her hands a   5   

face. She has breakfast at a   6    six forty. She leaves home at 7 o'clock. C   7    begin at ten to eight.

And she has four classes in the morning and two in the a   8   . At 3:30 she plays games with her f   9   .

She gets home at 5:30. She often watches CCTV news at 7:00 in the evening. And she goes to bed at

ten e   10    night.

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单项选择题

某机械设备预计使用10年、每年使用220个台班，大修理5次、每次的大修理费用为10000元，则该设备的台班大修理费为（）元。

A.2200

B.50000

C.227.27

D.22.72
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