慢性荨麻疹指的是反复发作病程超过多长时间以上()
A．1周
B．4周
C．6周
D．8周
参考答案：C
—How was your journey last week?
—Very interesting. The people there still keep the custom _____ the Ming Dynasty, which is different from other areas.
A．dating back to
B．dating back
C．dated back to
D．dated back
牙龈脓肿与牙周脓肿最不同的是（）
A.是否有真性牙周袋
B.炎症程度
C.是否有牙髓症状
D.患者的年龄
E.是否有创伤
创伤