— What do you think of the Chinese language today?

— Quite popular. It _____ in communicating with other countries. More and more foreign friends are

     learning Chinese. [ ]

A. plays an important role

B. is playing an important role

C. has played an important role

D. is being played an important role

世界上有四大文明古国之说。我们知道，文字是人类文明的标志之一，但它并非文明的本质。那么人类文明产生的根本标志是（ ）

A．金字塔、空中花园等世界奇迹的出现

B．古代哲学的产生

C．《汉谟拉比法典》等成文法典的出现

D．奴隶制社会的形成