往复低温泵机组的组成包括电机、皮带传动系统、出口管、进口适配器/进口驰放口和用于多缸泵的()。
A、集成器
B、组合集成设备
C、出口汇管设备
D、多层集流设备
参考答案:C
In the last two years, they _____ three major concerts. [ ]
A. have had
B. has had
C. made
D. have
万能角尺都有哪些用途?