跨阈步态见于()
A.腓骨肌萎缩症
B.小脑病变
C.脑性瘫痪
D.多发性硬化
E.亚急性脊髓联合变性
参考答案:A
We arranged to meet at 8:00, but she never ______.
A.turned down
B.turned off
C.turned over
D.turned up
简述气雾剂中药物通过肺吸收的机理。