食管静脉曲张时，食管吞钡X线检查表现为：食管轮廓呈（），曲张静脉呈（）。
参考答案：虫蚀样改变；蚯蚓样或串珠状负影
Miss Gao _____ this school since 1996.[ ]
A. has come to
B. came to
C. has taught
D. has been in
值班时睡觉，属B类过失。
