—When did you finish ______ your report?

—Last night. [ ]

A. writing        

B. write          

C. to write        

D. wrote

牙周袋底位于牙槽骨嵴的根方，牙槽骨为垂直型吸收的是（）。

A.龈袋

B.骨上袋

C.骨下袋

D.复杂袋

E.复合袋