The rest of the cave is made of limestone.(其余的都是由石灰岩组成。)
Most caves are formed by limestone, a carbonate rock.(大多数洞穴是由石灰岩形成的，这是一种碳酸盐岩。)
So we have been fairly thorough in our discussion about coral reefs, which of course are prominent, oceanic features made of hard limestone skeletons produced by tiny coral animals.(我们对珊瑚礁的讨论已经相当深入了；显然，珊瑚礁具有显著的海洋特征，由小型珊瑚动物制造的石灰骨架构成。)
These are generally fed by groundwater springs, and many issued from limestone massifs, such as the Atlas Mountains in Morocco.(它们通常由地下泉水供养，其中许多流自石灰岩山丘，如摩洛哥的阿特拉斯山脉。)
Most limestone and sandstone aquifers are deep and extensive but may contain groundwaters that are not being recharged.(大部分的石灰岩和砂岩的蓄水层都是深而广的，但可能含有不可再生的地下水。)
We've said that sulfuric acid dissolves limestone, right?(我们说过，硫酸可以溶解石灰石，对吗？)
When I was researching this for a study a few years ago, I visited a couple of these typical limestone caves, and they were all very wet, you know, from streams and rivers.(几年前我做这项研究时，我探访了其中几个比较典型的洞穴，它们都很潮湿，你们也知道这是因为小溪和河流的缘故。)
Cement is made from limestone.(水泥是由石灰石制成的。)
It was formed as a limestone cave during the glacial period.(它是于冰河时期形成的石灰岩洞。)
This gas is hydrogen sulfide, rises up and mixes with oxygen in the underground water that sits in the cracks and fissures in the limestone.(这种气体是硫化氢，上升后与石灰岩裂缝中地下水的氧气混合。)
