脊髓的抑制性中间神经元属于（）。

A.感受器 

B.传入神经 

C.神经中枢 

D.传出神经 

E.效应器

The radiotelephone safety message urgently concerned with safety of a person would be prefixed by the word（）.

A.Mayday

B.Pan

C.Safety

D.Interco