题干

如图是电解水的装置,下列关于电解水实验的说法正确的是(   )

A:水中加入少量的硫酸或氢氧化钠可以增强导电性

B:1是电源的负极

C:用燃着的木条检验产生的气体,a气体能燃烧,b气体能使木条燃烧的更旺

D:实验得出水由氢原子和氧原子构成的

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答案(点此获取答案解析)

A

同类题3

阅读下面短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项。

    My nephew's 10-year-old son came for a visit one hot, July weekend. I persuaded him to 1 inside and joined him in a game. After 2 for an hour, I suggested that we relax for a while. I 3 my favorite chair to let my neck relax. He left the room and I was catching a few enjoyable4 of peace.

    “Look, Alice,” he said excitedly as he 5 over to the chair where I was sitting. “I found a kite. Could we go outside and 6 it?” Looking out of a nearby window, I noticed it was 7 outside. “I'm sorry. Tripper,” I said, sad to see his 8 expression. “The wind is not 9today. The kite won't fly.”

    The 1010-year-old boy replied, “I think it's windy enough. I can get it to fly,” he answered 11he hurried out to the back door.

    He ran back and forth, as 12as his ten-year-old legs would carry him, looking back 13 at the kite behind. After about ten minutes of unsuccessful trying, he came back in.

    I asked, “How did it 14?” “Fine,” he said, not wanting to admit (承认) the failure. “I got it to fly some.”15 I heard him say secretly, “I guess I'll have to wait for the 16

    At that moment I heard another voice speak to my17“Alice, sometimes you are just like that. You want to do it your way 18waiting for the wind.”

    And the voice was 19. We usually want to use our own efforts to 20what we want to do. We must learn how to make use of “the wind”in the first place!