题目

一定质量的物体在水平拉力的作用下沿同一水平面做直线运动，其路程（ s ） —时间（ t ）关系如图所示，下列正确的是（ ） A． 物体 20s时的速度大于 8s时的速度 B． 0~12s物体所受的拉力大于 12s~24s物体所受的拉力 C． 0~12s拉力做的功大于 12s~24s拉力做的功 D． 0~12s拉力做功的功率小于 12s~24s拉力做功的功率听下面一段材料，回答第1至3题。 1. Who wants to book a room? [     ]A. The woman. B. John Devis. C. John Davis. 2. What kind of room does the man want to book? [     ]A. A single room with bathroom. B. A single room without bathroom.C. A double room with bathroom. 3. How long will the man stay at the hotel? [     ]A. Three nights. B. Four nights. C. Five nights.