题干

对于常温下pH=3的乙酸溶液,下列说法正确的是(  )

A:与等体积、pH=3的盐酸比较,跟足量锌粒反应产生的H2更多

B:水稀释到原体积的10倍后,溶液pH变为4

C:加入少量乙酸钠固体,溶液pH降低

D:加水稀释后,溶液中c(H+)和c(OH)都减小

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答案(点此获取答案解析)

A

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    My parents used to tell me how important the school was for me, but I didn’t think so. I didn’t   1    it. What I cared most was to hang out with my friends. But one thing let me finally  2  what my parents meant.

    One day, when I walked3a cellphone store, I saw an advertisement on its door. It was hiring(雇佣) new workers!

    “Sir, are you hiring people?” I went into the shop and asked. “Yes, but you  4 be the man who we need.” the manager answered. He looked at me for a few minutes from head to 5 .” Do you have a high school diploma(文凭)?”he asked, “do you have any working  6 ?”

    I felt so ashamed and  7  that I didn’t know what to say, so I just turned around and left.

I could not fall asleep that night, and I thought a lot about my future. “I must go to school  8  I can’t do anything without a good education,” I said to myself. I never went back to the store9  before I finished my study and got a diploma.

    Everything looked the same when I returned to the10: the same people and the same design. However,  11 with last time, I had more confidence this time. So it was a great chance for me.

I12  my diploma to the manager who once refused me. He looked at  13 for a while and then said to me, “Great, you are in.”

    Now I am still working in the same store. With this experience, I  14advise teenagers to attend to school. Education helps you have a bright future. Now I am not worried about my future because I still keep 15  in my free time. Education brings my future, doesn’t it?