与建的动力平衡无关的为()
A.向前的动力
B.向后的动力
C.左右的动力
D.上下的动力
E.内外的动力
参考答案:C
—Could you please pass the book on the shelf to me ?
—_____. [ ]
A. You are welcome
B. Yes , I could
C. Certainly . Here you are