A:Does she still enjoy working here
B:Does she wish to change a new jo
C:What kind of job does she do here
D:Where is she working at present
“种瓜得瓜,种豆得豆”、“老鼠生来会打洞”反映了生物的( )现象.
在0、227 、2 、93 、3.14、25 、-π2中,无理数的个数有( )
如图所示,质量为m的物体放置在倾角为α的斜面上处于静止状态,物体与斜面的滑动摩擦因数为μ,则物体所受摩擦力的大小为( )