牙周炎主要表现为牙槽骨，牙槽脊顶及骨硬板模糊、消失、牙槽嵴高度降低（）。
A.增生
B.肿胀
C.吸收
D.扩大
参考答案：C
艾泼斯坦测量装置
The young girl was _____ to ask such a simple question and nodded like the others.
A．shamed
B．ashamed
C．shameful
D．shameless
