If I were buried under the building during the big earthquake in Haiti, I would ask for help with

some __________ I learn from the teacher.[ ]

A. knowledge

B. knowledgeable

C. know

固定桥最重要的支持基础是（）。

A.牙周膜

B.牙槽骨

C.牙龈

D.结合上皮

E.黏膜