胆囊炎的病因不包括（）。
A.胆囊管梗阻，胆汁淤积
B.致病菌经淋巴传播
C.致病菌经血行传播
D.肝炎累及胆囊
E.胆管炎症累及胆囊
参考答案：D
______ world’s largest retailer, Wal-Mart, has opened its ______ third store in Beijing, which means the firm now has 52 stores in China.
A．The; a
B．A; a
C．The; the
D．The; /
封闭式问题的优点和缺点是哪些？
