These men are ____ cards on the train. [ ]
A. play
B. plays
C. playing
D. played
答案:C
袋深5mm,附着龈较窄,牙槽骨水平吸收,骨形态尚可,应选择
A.植骨术
B.改良Windman术
C.引导性组织再生术
D.牙周翻瓣术+骨成形术
E.冠向复位瓣术
---John, how did your English exam go?
-----I thought I ____,but in fact I came in the top 10% in the class.
A.should have failed
B.couldn’t have failed
C.might have failed
D.mustn’t have failed