A. What should I do B. Thank you, mom. C. Where have you been D. Yes, he is. E. What was wrong with him F. Were you sick G. Where is the hospital H. I’m sorry to hear that.
A. 对 B. 错
A. 由一系列相互联系相继发生的疫源地构成的 B. 传染源及其排出的病原体可以传播到达的地区 C. 病原体从受感染的机体排出后,再侵入易感机体前在外环境所经历的全部过程 D. 体内有病原体寄生繁殖且能排出病原体的人和动物 E. 人群作为一个整体对某种传染病易感受的程度