—Tom! Look at the man in black over there. Can you tell me ________?

—Oh! He is my friend, Jim. [ ]

A. what he is

B. who he is

C. how he is

重比重腰麻时，影响平面的因素除外（）

A.注射时病人的体位

B.穿刺针斜面方向

C.注射速度

D.穿刺针进入深度

E.药物剂量