问答题
试画出既能使三相异步电动机正、反连续运行，又能在正转或反转时点动的控制电路，要求具有过载、短路、欠压（失压）保护。
用SB4作正转点动，SB5作反转点动，画出控制电路如图所示。图中：......
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单项选择题 The main idea of the story is that（）.
单项选择题 When we dream，（）.
单项选择题 Which of the following is true？（）
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