流感病毒能使人和动物的红细胞凝集的结构是
A.M蛋白
B.HA
C.NA
D.核酸
E.核蛋白
参考答案:B
解析:HA为流感病毒包膜上的血凝集刺突,能使人和动物的红细胞凝集。
在人群中,长期携带致病性金黄色葡萄球菌者为()
A.25%
B.15%
C.5%
D.1%
E.0.5%
Luckily the man missed the high-speed train to Wenzhou, or he have been killed in the accident. [ ]
A. must
B. would
C. should
D. might