单项选择题

有一无线长载流I的螺线管，内部为真空，单位长度为n匝，有一电子以速度v沿螺线管轴线运动，则电子受到的洛伦兹力大小是。 A. 对 B. 错

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函数执行结束后，其内部的局部变量会被回收。（）

A．对
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单项选择题

The two largest legal families in the legal system of the world legal system, one is called the common law system, also known as the common law system, and the other is called the civil law system, also known as the civil law system. （） A. 对 B. 错