传染病的基本特征是
A．有病原体
B．有传染性
C．有流行病学特征
D．有感染后免疫
E．以上都是
参考答案：E
He is going to build a team that has a lot of potential and he thinks that is excites him.
A．that
B．which
C．what
D．as
情人节源自（）
A.罗马
B.美国
C.英国
