从上层到基层管理人员之间的何种职权形成指挥链？（）
A.直线职权
B.参谋职权
C.职能职权
D.管理职权
E.A和C
参考答案：A
交－直－交变频器，将工频交流电经整流器变换为直流电，经中间滤波环节后，再经逆变器变换为变频变压的交流电，故称为间接变频器
________ the whole week, I couldn't spare any time to visit him in hospital, though I had meant to.[ ]
A. Having fully occupied
B. Being fully occupied
C. Fully occupying
D. Fully occupied
