如图所示,小刚用200N的拉力在10s内把重320N的物体匀速提升了3m,滑轮的机械效率是 ____ ,拉力的功率是 ____ W.
读一读,连线。
① ____ A. What do you like? I like swimming.
② ____ B. - Do you like singing? -No, I don't.
③ ____ C. Hi, Sue. Can you draw? No, I can't.