按照标准化对象，通常把标准分为技术标准、管理标准和（）三大类。
参考答案：工作标准
We had just covered a distance of three miles _____ the engine of the car _____.[ ]
A. then; was broken
B. when; broke down
C. until; was failed
D. since; burst out
什么叫发车位数？
