在一堂物理活动课上，同学们正以“假如没有了……”为主题展开讨论。以下是几位同学提出的五个具有代表性的观点：①假如没有了地球引力，物体的质量仍然存在；②假如没有了摩擦力，一阵微风也可以吹动停在平直轨道上

题干

在一堂物理活动课上，同学们正以“假如没有了……”为主题展开讨论。以下是几位同学提出的五个具有代表性的观点：
①假如没有了地球引力，物体的质量仍然存在；
②假如没有了摩擦力，一阵微风也可以吹动停在平直轨道上的火车；
③假如没有了磁体周围的磁场，世界上就再也不会有电流的产生；
④假如没有了导体的电阻，导线将无法导电；
⑤假如没有了电磁波，我们将无法进行信息交流。
其中合理的是（）

A：①②

B：②③

C：③④

D：④⑤

上一题下一题 0.0难度选择题更新时间:2019-08-15 07:37:33

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A

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还原短文。

My mother is a kind and nice woman. ____ One Sunday night, when I was watching the film Harry Potter very happily. Mother asked me to go to bed. ____ that I didn't move. But for a while, I noticed that she didn't say anything. ____ I was so sad that I went into my room and cried. I thought "I have only two nights in a week to enjoy the TV. ____" The next day she cooked and talked with me as usual. I pretended not to hear, but she didn't mind and told me why she didn't allow me to watch TV ____ Then I understood her. I love my mother.

A. But she is very strict with me.

B. Because she wanted me to have a good rest.

C. Then she got angry and turned off the TV.

D. I love the film so much.

E. Why doesn't mother allow me to watch TV?

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