A:making; would study
B:to make; was studying
C:to make; had studied
D:making; had been studying
照样子写词语。
荡来荡去 ____
星期天,我们要去朝阳市人民公园游玩,不知如何乘车,应选择
王洪同学参加学校举行的跳绳比赛,他1min跳了120次,每次跳起的高度为5cm已知他的质量是40kg,求:(1)王洪同学每次跳起时需要做多少功?(2)王洪同学跳绳是的功率是多少?