题干

将一定量的锌粉加入到硫酸亚铁、硫酸铜和硫酸镁的混合溶液中,过一段时间后过滤,向滤渣中加入稀盐酸有气泡产生.关于该实验有以下说法:

①滤渣中一定含有锌

②滤渣中一定含有铜,可能含有锌

③向滤渣中加入稀盐酸,最后溶液一定变成浅绿色

④滤液中溶质一定含有硫酸锌和硫酸镁

⑤滤液的颜色不可能为浅绿色

以上说法中正确的个数是(   )

A:1个

B:2个

C:3个

D:4个

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答案(点此获取答案解析)

B

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    Robby was 11 when he took his first piano lesson. I1students begin at an earlier age,2I explained to Robby. Robby said it had always been his mother's dream to hear him play the piano. So I took him as a student.

Much3Robby tried, he4the sense of tone and basic rhythm. But be dutifully reviewed his lessons.

    Over the months he tried and tried, and he'd always say, “My mom's going to hear me play someday. ”But it seemed5 He just did not have any inborn ability.

    Then one day Robby stopped coming. I was glad, as he was a bad6for my teaching!I7he had decided to pursue something else.

    Several weeks later, my students were to have a recital(演奏会). To my surprise, Robby came, asking to play in the recital.

     “It is for8pupils, but you dropped.

     “My mom was sick. But I have been practicing. I've just got to play!” he insisted and I agreed.

    The night for the recital came. I put Robby up last in the program9I was to come up and thank all the students and play a finishing piece. I thought I could save his poor performance through my "curtain closer".

    The recital10well. Robby came up on stage. His clothes were wrinkled and his hair looked dirty. “How could his Mom?”I thought.

    Robby began and it was Mozart's work. I was not prepared for what I heard next. His fingers even11on the keys. After six and a half minutes he ended and people were all on their feet in wild12

    13and in tears I ran up and put my arms around Robby in joy. "I've never heard you play like that, Robby! How did you do it?"

    Through the microphone Robby explained :"Well , Miss Hondorf, remember I told you my mom was sick? Well.14she had cancer and15this morning. And well. . . She was born deaf, so tonight was the16time she ever heard me play. I wanted to make it17"

    There wasn't a18eye that evening. I thought to myself how much19my life had been for taking Robby as my pupil. However, he was the teacher, for it is he that showed me the meaning of20and love and believing in oneself.