龋病初期的临床特征中不包括（）

A.牙釉质是白垩色

B.牙齿的透明度下降

C.牙体硬组织脱矿

D.牙釉质出现龋坏

E.腔卫生极差

There _____ a lot of coal mines in the south, but many of them have been closed or are _____ be closed.

A．use to having; about to

B．used to be; to

C．use to having; going to

D．used to be; supposed to