Most people _______when the big earthquake took place in that area.
A:are sleeping
B:were sleeping
C:slept
D:sleep
m为在水平传送带上被传送的小物体(可视为质点),A为终端皮带轮,如图所示,已知皮带轮半径为r,传送带与皮带轮间不会打滑.当m可被水平抛出时,A轮每秒的转数最少是( )
It's white and fat.