绝大多数炭疽病是在病原微生物通过（）进入血流后发作的。
A.食物
B.皮肤伤口
C.被动物咬了以后
D.被节肢动物咬了以后
参考答案：B
— There is somebody at the door, who it be? Is it the postman?
— No, it be him, it's just six o'clock. It's too early. [ ]
A. may; can't
B. may; mustn't
C. will; won't
D. must; may not
