There _____ some water in the glass. [ ]
A. are
B. is
C. am
答案：B
能对抗肾上腺素收缩血管的药物是
A．阿托品
B．普萘洛尔
C．多巴胺
D．酚苄明
E．新斯的明
3（）
A．data flow diagram
B．entity relationship model
C．requirements model
D．object model
