As a saying goes, the wise man knows he knows nothing, _________ the fool thinks he knows all.

A．when

B．while

C．as

D．though

引起沙门菌属食物中毒常见的病原菌是

A．肠炎、猪霍乱、鸭沙门菌

B．猪伤寒、鼠伤寒、肠炎沙门菌

C．猪伤寒、火鸡、鸭沙门菌

D．牛伤寒、肠炎、鼠伤寒沙门菌

E．猪霍乱、鼠伤寒、肠炎沙门菌