In the market, vegetables are sold by _______ kilogram, I mean, by _______ weight.

A．the; 不填

B．不填; 不填

C．the; the

D．不填；the

腰穿后患者去枕平卧的目的是（）。

A.有利于脑部血液循环

B.防止脑水肿

C.减轻头晕、头痛

D.预防颅内压减低引起头痛

E.防止昏迷