If I ________ a policeman,I would catch the thief. [ ]
A. was
B. were
C. am
D. are
答案:B
伤寒并发症包括()
A.肠出血
B.肠穿孔
C.中毒性肝炎和中毒性心肌炎
D.中毒性脑病
E.溶血性尿毒综合征
能产生志贺样毒素的大肠埃希菌是()
A.ETEC
B.EIEC
C.EPEC
D.EHEC
E.EAggEC