潜伏性感染与病原携带状态的主要区别()
A.每种感染性疾病都存在
B.病原体一般不排出体外
C.体内存在病原体
D.不出现临床症状
E.以上都不是
参考答案:B
He made a(n)__________ with his wife "You take care of the children and I'll cook."[ ]
A. bargain
B. apology
C. promise
D. experiment
什么是结垢?