What the doctors really doubt is__________my mother will recover from the serious disease soon.

A．when

B．how

C．whether

D．why

下列因素可以造成牙髓或根尖周的慢性损伤，除外

A．创伤性咬合
B．磨牙症
C．窝洞充填物
D．修复体过高
E．备洞