食管癌的组织学分类中，最常见的是（）
A.腺癌
B.梭状细胞癌
C.髓样癌
D.燕麦细胞癌
E.鳞状细胞癌
参考答案：E
_____ by the belief that a key university is beneficial to one's future, many parents urge their children
to work hard. [ ]
A. Guide
B. Guiding
C. Guided
D. Having guided
蛋白质的平均含氮量为（）%，今测得1g样品含氮量为10mg，其蛋白质含量应为（）%。
