My friend asked me to go for _____ walk, but I don't think I've got _____ energy. [ ]

A a; /

B. the; the

C. / ; the

D. a; the

旋转零件的平衡状态有两种，即（）

A.轴向平衡

B.动平衡

C.静平衡

D.线性平衡