The______ look on his face suggested that he had passed the exam.

A．exciting

B．tired

C．tiring

D．excited

简单桩冠的牙体制备，残冠切除的高度为

A．龈 * * 中部

B．龈上0.5mm

C．近远中龈 * * 顶连线

D．颈1/3与中1/3交界处

E．龈下0.5mm