工字钢I16数字表示哪一项()?
A.工字钢截面高度160mm
B.工字钢截面高度16mm
C.工字钢截面宽度16mm
D.工字钢截面宽度160mm
参考答案:A
_____ everybody knows about it, I don't want to talk any more. [ ]
A. For
B. Even
C. Since
D. However
机械波波动方程为y0=0.04cos8π(t+0.02x),则()。
A.其波速为20m·s-1
B.其振幅为4m
C.波沿x轴负向传播
D.其周期为4s