椎管穿刺不经过（）
A.棘上韧带
B.棘间韧带
C.黄韧带
D.后纵韧带
E.以上均错误
参考答案：D
There is no in trying to persuade him to change his mind, for he never follows the advice of others.
A．doubt
B．point
C．difficulty
D．wonder
按连铸机生产铸坯的外形分类有方坯、（）、异形坯连铸机等。
A．板坯
B．弧形
C．立弯式
