克隆羊多莉长得非常像
A:供细胞核的母羊
B:供无核卵的母羊
C:代孕的母羊
D:ABC三种羊的一部分
使用如图所示的滑轮组提起水桶,已知桶中水的体积是4dm3,水桶重为8N,动滑轮重为6N,水桶向上匀速移动的速度为0.5m/s,忽略轴处的摩擦和绳重, 拉力F的功率为 (g = 10N/kg)( )
– Is that man Mr. Green?
– It _____ be him. He has gone to Paris on business.
His parents make him _______ at night.