收音机出境卫生检疫申报应当在出境收音机起飞前向检验检疫机构提交总申报单、货物仓单和其他有关检疫证件。( )
参考答案:对
Look out! Don't get too close to the house _____ roof is under repair. [ ]
A. whose
B. which
C. of which
D. what
如图所示,在轮C上固定有同轴小轮A,轮C通过皮带带动轮B,皮带和两轮之间没有滑动,A、B、C三轮的半径依次为rA:rB:rC=1:2:3.当小轮A在电动机的带动下匀速转动时,A、B、C三轮的角速度之比为______,A、B、C三轮边缘上各点的线速度大小之为______.