人体平衡时的稳定角是()
A.重心的倾斜角
B.重心垂线与重心到支撑面边缘的相应点连线的夹角
C.重心与支撑面边缘相应连线的夹角
D.重心垂线与重心到支撑面中心连线的夹角
参考答案:B
—Where is Joy?
—He _____ to the library[ ]
A. went
B. has gone
C. has been
突变率