在生理状态下，牙刚萌出时，唾液中的钙、磷进入釉质表层孔隙内沉淀、矿化形成磷灰石晶体，该现象为（）

A.生理性矿化

B.病理性矿化

C.自然再矿化

D.病理性再矿化

E.人工再矿化

Not much people realize that apples have been cultivated for over 3,000 years.

A．Not many

B．Not enough

C．Without many

D．No many