There is ____ Mr. Smith at the door who wants to speak to you.

A．a some

B．certain

C．some a

D．a certain

下前牙塑料联冠斜面导板矫治器的适应症包括（）

A.乳牙期功能性反

B.牙齿排列整齐、上前牙舌倾、反深且反覆盖小者

C.后牙反

D.乳牙期反覆小而反覆盖大者

E.以上都对