-Have you _ had Beijing Duck?
-Yeah. I love it. [ ]
A. ever
B. never
C. still
D. yet
答案:A
形成牙髓的是()
A.成釉器
B.牙 * *
C.牙囊
D.缩余釉上皮
E.Malassez上皮剩余
牙龈因失去食物按摩而出现了废用性萎缩是由于
A.牙冠轴面突度过大B.牙冠轴面突度过小C.牙冠轴面无突度D.牙冠颊外展隙不明显E.牙冠邻面无接触点