John opened the door. There _______ he had never seen before.   [ ]

A. a girl did stand      

B. stood a girl    

C. a girl did stood      

D. did a girl stand

长期应用抗病原微生物药可产生：

A．快速耐受性

B．成瘾性与戒断现象

C．抗药性

D．耐受性

E．反跳现象