— How many people are still leading ________ life under ________ poverty line in the world?

— Perhaps one fourth.[ ]

A. a; the  

B. a; a

C. /; /  

D. the; /

牙源性腺样瘤的好发部位为（）

A.上颌切牙区

B.下颌切牙区

C.上颌尖牙区

D.下颌尖牙区

E.磨牙区