中空义齿主要是用于修复下列哪项？（）

A.下颌骨缺损

B.唇腭裂序列治疗

C.上颌骨缺损

D.腭、咽部缺损

E.牙列缺损

There is actually an overlapped area of（）ocean regions somewhere in Western European Waters.

A.two

B.three

C.more than two

D.more than three