烤瓷冠戴用3天后咀嚼时修复牙出现咬合痛,检查有明显的叩痛,其原因是()
A.咬合时有早接触点
B.牙髓炎
C.龈炎
D.接触点略紧
E.接触点过松
参考答案:A
—Madam, Would you mind my opening the window?
— ________. My baby has a cold. [ ]
A. Of course not.
B. OK. I'll do it right away.
C. Yes, please.
D. Sorry, I'm afraid you can't
根据尺寸判断图6-87(b)所示平面连杆机构,是()。
A.曲柄摇杆机构
B.双曲柄机构
C.双摇杆机构