正弦交流电路的视在功率是表征该电路的（）
A、电压有效值与电流有效值乘积
B、平均功率
C、瞬时功率最大值
参考答案：A
单词拼写。
1. My _________ (照片) is on the wall.
2. What's _________ (在……下面) the bed?
3. Where are her _________ (钥匙)?
4. I don't _________ (知道) that.
5. The _________ (数学) book is on the dresser.
6. He _________ (需要) his hat.
7. The CDs _________ (是) in the drawer.
8. Does he _________ (有) a tennis racket?
9. _________ (让我们) play with them.
10. They like _________ (西红柿) very much.
对地电压在250v以上的电气设备为高压设备。
