如右图所示,理想变压器副线圈通过输电线接两个相同的灯泡 L1和L_爱下问搜题

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问题选择题

如右图所示,理想变压器副线圈通过输电线接两个相同的灯泡 L₁和L₂,输电线的等效电阻为R.开始时,电键S断开,当S闭合时,下列说法中正确的是（）

A．副线圈两端的输出电压减小

B．灯泡L₁更亮

C．原线圈中的电流增大

D．变压器的输入功率增大

答案

CD

开关S闭合，输出端电阻减小，输出电压由输入电压和匝数比决定，所以输出电压不变，输出电流增大，输入功率由输出功率决定，输入功率增大，输入电流增大，CD对；R两端电压增大，两灯泡两端电压减小，灯泡变暗，AB错；

完形填空

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，并在答题卡上将该项涂黑。
When I was in primary school, I got into a major argument (争论)with a boy in my class. I can't    what it was about, but I have never forgotten the    I learned that day.
I was    that I was right and he was wrong—and he was sure that I was wrong and he was right. The    decided to teach us a very important lesson. She    both of us up to the    of the class and    him on one side of her desk and me on   . In the middle of her desk was a large, round object. I could    see that it was black. She asked the boy what    the object was. "White," he answered.
I couldn't believe he said the object was white,    it was obviously black! Another    started between my classmate and me, this    about the color of the object.
The teacher told me to go to stand where the boy was standing and told him to come to stand where I had been. We changed   , and now she asked me what the color of the object was. I  answer, "White." It was an object with two    colored sides, and from his side it was white.    from my side was the color black.
My teacher taught me a very important lesson that day: You must    in the other person's shoes and look at the     through their eyes in order to    understand their view.

B．fortunately

C．conversation

B．was able to

B．differently

C．beautifully

D．surprisingly

A．unexpectedly

选择题

酒后驾车而发生重大车祸，造成伤亡事件，其主要原因是[ ]

A．发生了慢性的酒精中毒

B．酒精增加了肝脏负担

C．酒精使心肝血管受损

D．酒精影响了大脑的控制能力，导致行为失控