单位加速度信号的拉氏变换为()
A.A
B.B
C.C
D.D
参考答案:D
Though the passage is easy, I don’t think __________can understand it.
A.someone
B.anybody
C.everyone
D.nobody
机械密封的弹簧压缩量要按规定调整,要求误差为()毫米。
A.±5
B.±3
C.±2