A.重力就是地球的吸引力
B.物体的质量与重力成正比
C.把物体送到50000m高空,物体的重力变小,质量不变
D.1 kg=9.8N
答案:C
The doctor is not quite sure about what ________ the head injury will have on the patient. It may even cause brain damage.
A affect B effect C affection D effective
哪一个组件控制WX天线的稳定?
A、ADIRU
B、雷达收发机
C、雷达天线自身
D、不确定