题目

---What can he do?---___________.A. He wants to be in our school art festival B. He can sing and danceC. He likes football very much D. He is an actor 答案：【答案】B【解析】--他能做什么？--他能唱歌跳舞。A. He wants to be in our school art festival他想参加我们学校的艺术节； B. He can sing and dance他能唱歌跳舞。C. He likes football very much 他非常喜欢足球； D. He is an actor他是个演员。根据问句，故选B。 在水平力F作用下，重为G的物体沿墙壁匀速下滑，如图所示，若物体与墙壁之间的动摩擦因数为μ，则物体所受的摩擦力的大小为： ①μF ②μ(F＋G) ③G ④ [　　] A．①③ B．①④ C．②③ D．②④