易引起出血性膀胱炎的烷化剂是
A.环磷酰胺
B.氮芥
C.白消安
D.卡氮芥
E.甲氨蝶呤
参考答案:A
Pollution has reached ______ high levels in some urban areas, which is quite worrying. [ ]
A. disturbingly
B. slightly
C. exactly
D. flexibly
食管腐蚀伤后最常发生食管狭窄的部位是()
A.食管入口
B.左支气管压迹处
C.主动脉弓压迹处
D.食管下段横膈以下
E.贲门处