题型:问答题 简答题 —What ____ does she like? —Baseball. She ____ every day. [ ]A. exercise; exercise B. exercise; exercises C. exercises; exercise D.exercises; exercises 查看答案
题型:问答题 简答题 如图所示,高h=2m的曲面固定不动.一个质量为1kg的物体,由静止开始从曲面的顶点滑下,滑到底端时的速度大小为4m/s.g取10m/s2.在此过程中,下列说法正确的是:( )A.合外力做功8JB.物体克服阻力做功12JC.机械能保持不变D.物体的机械能增加了12J 查看答案