She hasn't told me when she ______ her new novel, but she says when she ______ it, I will be the

first reader. [ ]

A. will finish, will finish

B. finishes, finishes

C. will finish, finishes

D. finishes, will finish

如图所示，质量为m，带电量为-q的粒子，从两平行电极板正中央垂直电场线和磁感线以速度v飞入．已知两板间距为d，磁感强度为B，这时粒子恰能直线穿过电场和磁场区域（重力不计）．今将磁感强度增大到某值，则粒子将落到极板上．当粒子落到极板上时的动能为______．