(2013·杭州模拟)Encouraged by my science teacher, I set about my studies on developing my product, 　　　　I hope I will succeed in applying for a patent(专利权).

A．with whom

B．to whom

C．through which

D．for which

如图所示，斜面的倾角为，质量为的滑块距挡板P的距离为，物块以初速度沿斜面上滑，滑块与斜面间的动摩擦因数为，滑块到达斜面最高点后能返回，若滑块每次与挡板P相碰后均以等速率弹回，则滑块能通过的总路程为                            ．