中国石油大学 / 中石油
正确率：100%
28. The different systems in a rotary drilling rig are ___________________________.
A、the power system
B、the hoisting system
C、the safety system
D、the circulating system
E、the rotating system
A、the power system
B、the hoisting system
C、the safety system
D、the circulating system
E、the rotating system
参考答案：