学生们通过口头传播得知了这个中心。

Students learned of the center ___by ___word ___of ___mouth.

过去，新闻主要通过口头传播，一个人需要几天甚至几周才能意识到世界另一端发生的事件。

In the past news traveled mostly ___by ___word ___of ___mouth and it took days and sometimes weeks before a person would become aware of an occurrence on the other end of the world.

谣言通过口头传播得很快。

The rumor spread quickly ___by ___word ___of ___mouth.