如图所示，用滑轮组匀速提起1200N的重物，拉力做功的功率为1500W，绳子的自由端向下拉的速度为3m/s，地面对人的支持力为N1，不计绳重和摩擦．
⑴____ A. cousin B. sister C. Miss D. nurse
⑵____ A. there B. here C. where D. bear
⑶____ A. tall B. ball C. also D. all
⑷____ A. this B. thin C. there D. they
⑸____ A. uncle B. orange C. student D. stand
