问题
选择题
现榨的苹果汁在空气中会由淡绿色变为棕黄色．你猜测其原因可能是（ ）
A．苹果汁中含有OH-
B．苹果汁中含有Cu2+
C．苹果汁中的Fe2+变成Fe3+
D．苹果汁中含有Na+
答案
金属离子颜色亚铁离子淡绿色，铁离子黄色，现榨的苹果汁在空气中会由淡绿色变为棕黄色，所以苹果汁中的Fe2+变成Fe3+．
故选C．
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现榨的苹果汁在空气中会由淡绿色变为棕黄色．你猜测其原因可能是（ ）
A．苹果汁中含有OH-
B．苹果汁中含有Cu2+
C．苹果汁中的Fe2+变成Fe3+
D．苹果汁中含有Na+
金属离子颜色亚铁离子淡绿色，铁离子黄色，现榨的苹果汁在空气中会由淡绿色变为棕黄色，所以苹果汁中的Fe2+变成Fe3+．
故选C．
A lady once wrote a long story. She sent it to a famous editor. After a few weeks the editor 21 the story to her. The lady was 22 . She wrote back to the editor: “Dear Sir. Yesterday you sent back a story of mine. How do you know that the story is not good? You did not read it. 23 I sent you the story, I pasted together pages 18, 19 and 20. This was a 24 to see whether you would read the story. When the story came back yesterday, the pages were 25 pasted together. Is this the way you read all the stories that are sent to you?” The editor wrote back: “Dear Madam, At breakfast then I have an egg. I don’t have to eat the whole egg in order to discover(发现) that it is bad.”
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