慢性牙周炎与慢性单纯性龈炎的鉴别要点是
A．牙龈红肿 B．牙石沉积C．牙龈出血 D．牙槽骨吸收E．龈缘糜烂
参考答案：D
-Can those at the back of the classroom hear me?
-No problem. [ ]
A．seat
B．sit
C．seated
D．sat
如何加强强余震防范措施？
