以下哪种属于颌间固定 （）
A.颌间结扎
B.小环结扎
C.连续多环结扎
D.带钩牙弓夹板
E.头帽固定
参考答案：A, B, C, D
The exam was very difficult but everyone ______ pass.
A．had to
B．would
C．could
D．was able to
