阀门的型号标注中,阀门连接形式代号“4”表示()连接。
A.内螺纹
B.外螺纹
C.焊接
D.法兰
参考答案:D
---- What did Walt Disney do after ________ school?
---- He sold newspaper and delivered mail.
A.leave
B.left
C.leaves
D.leaving
腰椎管狭窄症最突出的症状是:()
A.腰腿痛
B.下肢麻木
C.腱反射改变
D.直腿抬高试验(+)
E.间歇性跛行