哪些是牙体缺损修复后引起龈炎的原因()
A.食物嵌塞
B.咬合不平衡
C.边缘过长
D.边缘不密合
E.光洁度差边缘粗糙
参考答案:A, C, D, E
Is that _____ pencil case? [ ]
A. he
B. him
C. his
D. he's
滑动轴承按所受负荷方向可分为()。
A.轴向轴承
B.径向轴承
C.推力轴承
D.径向推力联合轴承