③
A.事务
B.用户
C.分析
D.系统
参考答案:A
In the office I never seem to have time until after 5:30 p. m., _____ many people have got home.
A whose time B. by that time
C. on which D. by which time
考虑摩擦的转动副,不论轴颈在加速、等速、减速不同状态下运转,其总反力的作用线()切于摩擦圆。
A.都不可能;
B.不全是;
C.一定都