下列哪项不是引起上消化道出血的常见病因（）
A.消化性溃疡
B.急性胃黏膜病变
C.胰腺炎
D.胃癌
E.食管胃底静脉曲张
参考答案：C
---After graduation, more senior students in the mainland are applying for admission to Hong Kong
University.
---________. But studying in Hong Kong may cost more. [ ]
A. I hope so
B. That’s the case
C. Not really
D. That sounds reasonable
已知A、B、C三点在同一直线上，AB=16cm，BC=10cm，M、N分别是AB、BC的中点，则MN等于______．
