People have disclosed a secret in Dunhuang grottoes.

人们还在敦煌石窟发现这样一个秘密.

People have disclosed a secret in Dunhuang grottoes .

人们还在敦煌石窟发现这样一个秘密。

The study of Dunhuang grottoes are known as Dunhuangology.

对敦煌石窟的研究又叫敦煌学.

What were needed for the protection of the Dunhuang grottoes were knowledge and science.

敦煌石窟的保护需要的是知识和科学.