上消化道出血最常见的病因是（）
A.消化性溃疡
B.胆道疾病
C.急性糜烂性胃炎
D.贲门黏膜撕裂症
E.肝硬化食管静脉曲张破裂
参考答案：A
在骨骼疾病的诊断酶学中最重要的酶是（）
A.LDH
B.CK
C.ALP
D.ACP
E.ALT
The recent conference on the effective use of the seas and oceans was another attempt resolving major differences among countries with conflicting interests.()
A. resolve
B. resolves
C. to resolve
D. being resolved
