引起继发性腹膜炎的病因不包括（）
A.急性阑尾炎
B.溃疡穿孔
C.胆囊穿孔
D.肝硬化腹水感染
E.手术污染
参考答案：D
Look! Some students _____ games under the big tree. [ ]
A. play
B. are play
C. are playing
D. played
简述竖向设计的内容。
