题目

如图，一质量为m的木块置与倾角为37°的粗糙斜面上，木块恰好沿斜面匀速下滑，则木块与斜面间的动摩擦因数为（     ）A. 0.6        B.0.75       C. 0.8        D. 无法确定  答案：B解析:略  ____ you are dismissed. A. Neither you go nor                B. Either you go or       C. Whether you go or               D. Both you go and