接触器熔断后，触头不能分开，产生这一故障的可能原因是（）
A.短路不断裂
B.反作用弹簧太紧
C.触头熔焊
D.剩磁过大
参考答案：C
根据句意和首字母提示填空。
1. Would you like to w________ the football game?
2. Can you s________ your photos to me?
3. He s ________ he was in the library.
4. don't know how to answer the question, do you have any i________?
5. Can you p________ bring a cup of tea to me?
五味子保肝的主要药效成分是（）
A.香豆素
B.木脂素
C.蒽醌
D.生物碱
E.黄酮
