题目

--- The room is dirty. _____ we clean it?    --- Of course.     A. Will                              B. Shall                                 C. Would                             D. Do 答案：B以下是我们在生活中可以见到的几种现象：①一阵风把灰尘吹得漫天飞舞；②篮球撞击在篮板上被弹回；③用力捏小皮球，皮球变瘪了；④用力揉面团，面团形状发生变化．在这些现象中，物体因为受力而改变运动状态的是（　　）A．①②B．②③C．③④D．①④