This is _________ bike. They share it with each other.
A:Mike's and Jim's
B:Mike's and Jim
C:Mike and Jim's
D:Mike and Jim
用如图所示的滑轮组在10s内将300N的重物匀速提升3m,已知动滑轮重30N,不计绳重和摩擦,则拉力大小为____N,拉力的功率为____W.
下列关于汉唐明清中枢的演变图例正确的是
几种物质的沸点( 1 个标准大气压)