then the calcite is deposited on the floor of the cave 方解石就会在洞穴地面上沉积
Each drop leaves behind only a miniscule amount of calcite, 每滴水珠只会留下极少量的方解石微粒
some of that is deposited as a mineral - 其中的一些就会沉淀为一种矿物
are the main ingredient of birds' nest soup 是燕窝羹的主要成分
The pure white nests of cave swiftlets 洞金丝燕的纯白燕窝
For 500 years people have been harvesting the nests of cave swiftlets. 500年来 人们一直采集洞金丝燕的燕窝
and using ladders made from forest vines the gatherers climb into the highest reaches of the cave 采集者利用树藤编成的梯子爬到洞穴的最高处
Their little cup-like nests are made entirely from threads of saliva. 它们小巧的杯状燕窝完全由唾液丝筑建
by the morning the vast majority will be back in the safety of the cave. 到了早上 大多数蝙蝠 仍会安然无恙地回到洞中
the stream of bats form a doughnut-shaped ring. 即在空中组成一个面包圈一样的队列