Clark电极的基本组成包括（） A.pH电极 B.铂丝阴极 C.Ag－AgCl电极

阅读短文，用方框内所给单词的正确形式填空，使短文意思通顺、完整。每词限用一次。方框中有两个词是多余的。

surprise     mad    the other    about    from    time     another    on    keep    happen  see   make

Do you learn 小题1:        your mistakes? I hope so. But have you 小题2:      the same mistake twice? I have. Sometimes I make the same mistake three or four小题3:    !
Sometimes, good things 小题4:     because of mistakes. Once I got 小题5:     the wrong train. That was a big mistake .But on that train. I 小题6:    a good friend I was so happy I made that mistake!
小题7:      time I ruined（破坏）a surprise. My mother planned a 小题8:     party for my father. She told me it was a secret. But I was just a little boy and I couldn’t小题9:    the secret. I told my father about the party .At first, my mother was小题10:     at me. But then my father said he was happy he knew about it. He said he didn’t like surprises.