The power elements of the hydraulic system are ().
A. motor
B. hydraulic pump
C. hydraulic cylinder
D. hydraulic valve
查看答案
Which of the following is used as a component in hydraulic power unit?
A. pressure gauge
B. filler gauge
C. pump
D. reservoir
Rotary motion in a hydraulic power unit is achieved by using
A. hydraulic cylinder
B. pneumatic cylinder
C. both hydraulic and pneumatic cylinder
D. none of the above
Which of the following is used as an accessory in hydraulic power unit?
A. pumps
B. valves
C. motor
D. reservoir
秩相等是两个同维向量组等价的 条件。
A. 必要
B. 充分
C. 充分必要
D. 既不充分也不必要
微信支付 
支付宝支付