钻床变速前应（）。
A、停车
B、取下钻头
C、取下工件
D、断电
参考答案：A
根据句意及所给首字母，完成单词。
1. Are you learning to d _____ pictures?
2. There is a big tree in f _____ of Tom's house.
3. Most of the students in our class think math is d _____.
4. My room is on the s _____ floor.
5. The bus will take you there. You can't m _____ it.
