单项选择题
A.regulating the oil flow with the six-way valve
B.moving the automatic differential valve
C.moving the receiving tele-motor which regulates the two-way valve
D.varying the angle of a tilting box or eccentricity of a floating ring
单项选择题 Which characteristic or condition will have the greatest effect on increasing a hydraulic oils viscosity?（）
单项选择题 When there is no movement of the rams on an electro-hydraulic steering gear, the tilting box of the running pump is （）.
单项选择题 The structural members of the hull extending in a fore and aft direction are called （）.