题目

质量相等的物体A和B并排放在光滑水平面上，现用―水平推力F推物体A，同时在与力F相同方向给物体B一冲量I，两物体都开始运动，当两物体重新相遇时，所需时间是    A．        B．2       C．2       D．  答案：BThe boat _____ like a duck. [     ]A. isn't lookB. don't lookC. doesn't lookD. doesn't looks