Apples are usually sold by ______weight, and eggs are sometimes sold by ______ dozen.

A．the; the

B．不填; a

C．不填; the

D．the; a

“When in Rome，do as the Romans do。”这句谚语反映的实质问题是[ ]

A．罗马文化的渗透

B．被征服者对罗马统治者的反抗

C．东方文化对罗马文化的影响

D．罗马帝国交通发达