所受重力为G的木块在水平力F作用下,压在竖直墙面上静止,已知墙与木块间的动摩擦因 发布时间:2017-06-25 01:53 │ 来源:www.tikuol.com 题型:选择题 问题: 所受重力为G的木块在水平力F作用下,压在竖直墙面上静止,已知墙与木块间的动摩擦因数为μ,那么墙对木块的摩擦力为( )A.0B.GC.大小无法判断D.μF
题型:选择题 ---Where is George? He said he would meet me here at 3 o’clock.---He seems ________ with Mr. Brown in the office.A.to talkB.to have talkedC.to be talkingD.to be talked 查看答案
题型:选择题 Burglars(窃贼)had while we were away on holiday. [ ]A. broken into B. broken in C. broken down D. broken out 查看答案