危险性分值在()之间为中度风险。
A.10~20
B.20~70
C.70~160
D.160~320
参考答案:C
移动凸轮作( )运动而推动从动杆作直线往复移动或摆动。
A.直线
B.曲线
C.回转
D.摆动
The policeman asked the small girl _____.[ ]
A. why she was crying
B. why was she crying
C. why she is crying
D. why is she crying