— What do you think of Zhang LiangYing's English songs?

— Very attractive and lively. Almost no other Super Girls can sing _____ at present, I think.

A．well

B．best

C．better

D．the best

患者，男，65岁。右上后牙充填物反复脱落，需进行全冠修复。查远中邻大面积银汞充填。无松动，无叩痛，牙根暴露3mm，临床牙冠长。全冠龈边缘的最佳位置是（）。

A.平齐龈缘

B.龈缘以上

C.达龈沟底

D.龈沟内1mm

E.龈沟内0.5mm