位于后纵隔的有（）
A.迷走神经
B.交感干
C.胸主动脉
D.胸导管
E.奇静脉
参考答案：A, B, C, D, E
The teacher asked the girl again, raising his voice a bit, but still _____ no answer.
A. receiving
B. received
C. receive
D. to receive
对沙门氏菌属进行（）试验为阳性。
A.水扬苷
B.ONPG
C.鸟氨酸
D.棉子糖
