从方框中选择最佳选项完成对话，有两项多余

a. Maybe you're right.

b. Is there anything wrong?

c. I'll try to understand her.

d. She nags me about almost everything.

e. That's a good idea.

f. But she doesn't like it at all.

g. Could I use your telephone, please?

A: Hello, Xiao Hong!

B: Hello!

A: You look a little upset. ____

B: Yes. It's just my mom. She always nags(唠叨)me.

A: Really? What does your mother nag you about?

B: ____“Get up now. . . . Everything must be in place. . . .  Don't forget your piano lesson. . . . ”

A: Well, all the mothers like saying these words to their children.

B: Also, I'm fond of pop music. ____We don't have the same interest in many things.

A: ____ But I should say she nags you because she cares about you. You're lucky to have such a good mother.

B: I agree with you. ____

A: That's right. Understanding is important. If your mom knows that everything is fine, she will never nag.

如图所示，电源电压保持不变，断开开关S₃，分别只闭 合开关S₁和只闭合开关S₂时电阻R₁和R₂两端的电压之比为4︰3，电阻R₃两端的电压之比为2︰3。只闭合开关S₂时 ，电阻R₃消耗的电功率为100W。求：

（1）只闭合开关S₁时，电阻R₁和R₃消耗的电功率之比。
（2）开关S₁、 S₂、S₃都闭合时，电路消耗的总电功率。