对于正常运行时产生火花或电弧的电气设备必须具备()装置。
A.远控
B.近控
C.联锁
D.保护
参考答案:C
按要求完成下列句子。
1. He wrote a letter to his dad in New York. (改为现在进行时)
Now he ____________ ____________ a letter to his dad in New York.
2. It's a quarter to ten. It's time for cartoons. (改为近义句)
It's nine ____________. It's time ____________ ____________ cartoons.
3. He does some exercise every morning. (改一般疑问句)
____________ he ____________ exercise every morning?
4. She saw the film last year. (对画线部分提问)
____________ ____________ she ____________ the film?
5. The station is about 6 kilometers away from our school. (对画线部分提问)
____________ ____________ is the station from your school?
6. She is going to buy a new hat, because her hat is too old. (对画线部分提问)
____________ ____________ she going to ____________ a new hat?
接触性皮炎的发病机制有()
A.原发性刺激反应
B.原发性致敏反应
C.接触性刺激反应
D.接触性致敏反应