下列哪种接地属于工作接地（）。
A、变压器中性点接地
B、互感器二次侧接地
C、电器设备外壳接地
D、零线接地
参考答案：A
看图完成对话。
①— Can you play ____ ?
— Certainly. I can play it well.
②— Does Tom have a _____?
— Yes, he does.
③— Do you want to play _____?
— Yes, I do.
④— I don't have a _____ ?
— Don't worry.You can use mme
⑤— Hello, Peter! I have a new_____.
— Oh, It's very mce.
茶碱类主要用于治疗（）。
A.支气管哮喘
B.支气管扩张
C.气管炎
D.肺不张
E.慢性阻塞性肺炎
