These Bornean caves are among the biggest in the world 婆罗洲的这些洞窟是世界上最大的洞穴

133. As soon as its nest is removed a bird will immediately build another.
     燕窝被摘去后 金丝燕很快又会再吐一个
134. So, as long as this valuable harvest is properly controlled,
     所以 只要这种利润可观的 采摘行为得到适当控制
135. the colonies will continue to flourish.
     燕群仍旧可以长盛不衰
136. These Bornean caves are among the biggest in the world
     婆罗洲的这些洞窟是世界上最大的洞穴
137. and they're still getting bigger
     它们仍在不断扩大
138. as each year rainwater eats away a little more limestone.
     因为每年雨水都会侵蚀掉少许石灰岩
139. But water in caves doesn't only erode.
     可是洞里的水不光只是侵蚀

来自《行星地球 第一季 第四集 Planet Earth S01E04 洞穴》第 136 行