有以下数组声明语句:OptionBase1:DimA(3,4),则数组A有()个元素。
A.3
B.4
C.12
D.20
参考答案:C
如图所示一矩形断面通风管道,断面尺寸为1.2m×0.6m,空气密度ρ=1.20kg/m3,流速v=16.2m/s,沿程阻力系数λ=0.0145,流程长度L=12m的沿程压强损失为()N/m2。
A.28.14
B.31
C.34.25
D.45.51
It turned out that one of the children I thought a girl was________a boy.[ ]
A.specially
B.usually
C.especially
D.actually