进行交流耐压试验时，对升压速度的要求是：40%以下的试验电压一般不受限制。
参考答案：对
用所给单词的适当形式填空。
1. Let _____ (they) watch TV now.
2. How many photos _____ Lily _____ (have)?
3. Please _____ (listen) the teacher carefully.
4. Mary likes _____ (write) in English.
5. Tim _____ (like) math, he thinks it isn't interesting.
下列装置中的（）是防止雷电侵入波的避雷器。
A、避雷针
B、避雷网
C、阀型避雷器
D、避雷带
