呕吐可分为（）
A.反射性呕吐
B.中枢性呕吐
C.前庭障碍性呕吐
D.消化性呕吐
E.顽固性呕吐
参考答案：A, B
My mother is English teacher [ ]
A. a
B. an
C. the
液化石油气瓶的检验周期？
