It is different from any libraries you know: It is a secret underground library, and only people in Darayya know where it is.

它不同于你知道的任何图书馆：它是一个秘密的地下图书馆，只有德拉雅的人才知道它在哪里。

youdao

This is one of the top-secret underground bases in the Soviet Union.

这是前苏联的绝密地下基地之一。

youdao

From a secret underground base scientists try to find a way to fight the aliens.

从一个秘密的地下基地科学家试图找到一种方法打外星人。

youdao

What we don't get here is a sense of whether there really is an alternate secret postal system that serves a sort of underground of private networks.

在这里我们所不明白的是，是否真的存在一个,提供地下的,私密的通信服务的，秘密邮政系统。

耶鲁公开课 - 1945年后的美国小说课程节选

Visitors shuffle through a secret underground passage leading from the wardrobe of a Sea Tiger leader to his garden.

ECONOMIST: A rebel stronghold becomes an unlikely tourist trap

Yet last month American spy-statellite pictures revealed North Koreans working on a secret underground complex, which could possibly be used for making nuclear weapons or the missiles to carry them.

ECONOMIST: North Korea

The exposure of the previously secret underground Fordow enrichment facility near Qom by outside intelligence agencies in 2009 made a further mockery of attempts to claim the programme was entirely peaceful.

ECONOMIST: Nuclear diplomacy