单项选择题
Which of the following terms could be applied to the simple definition the energy of motion?（）
A.Electrical energy B.Thermal energy C.Potential energy D.Kinetic energy
单项选择题 The delivery rate of an axial-piston hydraulic pump is controlled by varying the position of the （）.
单项选择题 Badly leaking refrigeration compressor discharge valves will cause（）.
单项选择题 Mechanical energy in transition is referred to as （）.
