搜题请搜索小程序“爱下问搜题”
问题 选择题

下列检验离子的方法及结论正确的是（　　）

A．向某溶液中滴加AgNO3溶液后产生白色沉淀，说明原溶液中含有Cl-

B．向某溶液中滴加BaCl2溶液后产生白色沉淀，说明原溶液中含有SO42-

C．向某溶液中滴加稀硫酸后生成无色气体，说明原溶液中含有CO32-

D．向某溶液中滴加NaOH溶液后生成蓝色沉淀，说明原溶液中含有Cu2+

答案

答案：D

补全对话，情景问答

根据对话情景，在空白处填上一个适当的单词，使对话完整通顺。

A: Your English is very good, Zhang Lei. Can you please tell me 1_____ you learn it?

B: I learn English  2_____ speaking as much as possible in and 3_____ of class.

A: Do you learn English by watcng English language 4_____?

B: Yes, 5_____often. And I also listen to tapes.

A: Do you study grammar?

B: No, I never study grammar. It's 6 _____ and I don't think it is helpful.

A: I can't get the pronunciation right. What should I do?

B: Don't worry. Try to speak English as 7_____ as you can. You can also 8_____ it with your friends.

A: I enjoy reading English magazines, but my reading is usually slowed down by too many new words.

    9_____ should I do then?

B: You can always write the new words on a small piece of paper and study them when you are free.

A: Thank you very much!

B: It's my 10______.
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计算题

用油罐车运输密度为0.9g/cm3的原油，每节油罐车的容积是50m3，运送900t原油，需要多少节油罐车？
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