ItisdesirablethAttheairplane()aslightaspossiBle.
A. is
B. were
C. Be
D. hadbeen
纵向衣通要求柜体的安装净空深度大于多少。()
A. 250mm
B. 300mm
C. 310mm
D. 350mm
Wecamefinally()theconclusionthatshehadbeentellingliesallthetime.
A. of
B. into
C. to
D. At
直径为D的圆管,在半满流(即水深为D/2)条件下,其水力半径R为()
A. R=D
B. R=D/2
C. R=D/4
D. R=D/8