以下关于增加冠桩固位的方法正确的是（）。

A.根管口预备一小肩台

B.增加桩与管壁的密合度

C.选用优良粘结剂

D.尽可能去净根管内壁上附着的充填材料

E.尽可能去除残冠硬组织

—______ Rose ______ Jack watched Prince William's wedding on TV yesterday.

—What a pity! They misses the exciting moment. [ ]

A. Both, and

B. Not only; but also

C, Either; or

D. Neither, nor