The underground chamber remained a secret for nearly 1, 600 years, until an archaeologist noticed rectangular patches of soft clay in the pyramid's floor—a telltale sign of a grave.

这地下墓室的秘密尘封了近1600年之久，直到一位考古学家发现了在塔内地面上的矩形软土——它泄露了墓穴的秘密。

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That sign means: we mustn't eat or drink on the underground.

那个标牌意思是：地铁内不准吃喝。

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The prolonged saga of the semi-privatisation of London's underground shows no sign of being resolved.

ECONOMIST: Transport

New sources need to be found underground and regulators need to sign off before a shovel can even hit the ground.

FORBES: Magazine Article