Alan is _______ honest boy. You can believe him. [ ]
A. a
B. an
C. the
D. ×
答案:B
下牙槽神经阻滞麻醉的注射点是
A.翼下颌皱襞中点
B.翼下颌皱襞中点外3~4mm
C.颊部三角形颊脂垫尖
D.下颌小舌
E.下颌小舌上方
倒闸操作前后应注意哪些问题?