培训是企业提升员工能力的唯一途径。( )
参考答案：错
I ______ my Chinese teacher in the supermarket near my house, which was out of my expectation. [ ]
A. came out
B. came across
C. came about
D. came along
实心圆轴受扭，若将轴的直径减小一半，其他条件不变，则圆轴两端截面的相对扭转角是原来的( )倍。
A．2 B．4C．8 D．16
