采用阴离子表面活性剂测定含量的药物是
A．盐酸苯海拉明注射液
B．盐酸苯海索片
C．盐酸多巴片
D．硫酸苯丙胺
E．对乙酰氨基酚
参考答案：A
----Will Barbara come to our party?
----I am not sure, because he ____ go to the concert with his friend.
A．can
B．must
C．should
D．might
论述四冲程发动机的换气过程中，为什么要排气提前？
