关于队列研究,下列哪一项是正确的()
A.不能计算AR值
B.适用于罕见病
C.随机分组
D.可以研究一种暴露与多种结局的关系
E.研究周期短,省时省力
参考答案:D
下列与免疫失调无关的疾病是[ ]
A.血友病
B.过敏性鼻炎
C.艾滋病
D.风湿性心脏病
根据句意和所给中文写出句中所缺的单词.
1. May I _____ (介绍) my best friend Amy to you, Sandy?
2. I think it's our _____ (职责) to protect the environment.
3. The cinema has _____ (出口) on its three sides.
4. Will you please pay _____ (注意力) to what I am saying?
5. How many _____ (客人) were there in yesterday's party?