如图,一个人站在水平地面上的长木板上用力F向右推箱子,木板、人、箱子均处于静止状态,三者的质量均为m,重力加速度为g,则( ) A.箱子受到的摩擦力方向向右 B.地面对木板的摩擦力方向向左 C.木板对地面的压力大小为3mg D.若人用斜向下的力推箱子,则木板对地面的压力会大于3mg 答案:C21、Tommy is _______ captain of the class team at school
and he is also _____ member of _____ Senor High team.
A./ ; a ; the
B.the ; the ; the
C.the ; a ;
the D./
; / ; the