— I'd like a pen which ______ well.

— Will this one ______?[ ]

A. is written; do

B. writes; do

C. writes; work   

D. is written; work

骶管穿刺必须经过下列哪一种结构()

A．骶棘韧带

B．后骶尾韧带

C．骶管

D．骶骨前筋膜

E．以上都是