如图所示，电路中三个完全相同的灯泡a、b和c分别与电阻R、电感L_爱下问搜题

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问题选择题

如图所示，电路中三个完全相同的灯泡a、b和c分别与电阻R、电感L和电容C串联，当电路两端接入电压为u＝220sin100 πt V 的交变电压，三个灯泡亮度恰好相同。若保持交变电压大小不变，将频率增大到60Hz，则将发生的现象是

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A．三灯亮度不变

B．a不变、b变亮、c变暗

C．三灯均变亮

D．a不变、b变暗、c变亮

答案

答案：D

判断题

产蛋鸡配合饲料中游离棉酚不超过20mg/kg。

补全对话，情景问答

从方框中选择恰当的句子填入空白处。

A. How are you going to do that?
B. I'm not sure yet.
C. What are you going to be?
D. I'm going to be an actor.
E. Who is your favorite actor?

A: 1 _______ when you grow up
B: I'm going to be a professional soccer player.
A: 2 _______.
B: I'm going to practice playing soccer every day.
A: Where are you going to work?
B. 3 _______ Maybe, Beijing or Shanghai. How about you?
A: 4 _______, and I'm going to take acting lessons for my dream.
B: 5 _______.
A: I like Zhou Jielun best.
B: I wish your dream will come true.
A: Thank you very much!