在精基准的选择中，选择加工表面的设计基准作为定位基准这遵循了（）原则。
A、基准重合
B、互为基准
C、自为基准
D、保证定位可靠
参考答案：A
-- I didn't realize how popular the restaurant was until I made a reservation the other day.
-- I beg your pardon, but when __________?
A．was you realized it
B．it was that you realized it
C．you realized it
D．was it that you realized it
从活动水平的角度看，个体的实践活动由生理、__________和__________三种不同层次和内容的活动构成。
