男性,20岁,体格检查时胸部透视发现上纵隔影增宽,CT检查示上纵隔占位,下列哪项诊断最不可能
A.畸胎瘤
B.胸骨后甲状腺肿
C.胸腺瘤
D.支气管囊肿
E.降主动脉瘤
参考答案:E
It's a common ____ for young people to pay a New Year's visit to their elders. [ ]
A. sense
B. practice
C. rule
D. scene
城市基础设施建设存在的主要问题?