5 Blue Holes ：Some of the Least Explored Areas on Earth 蓝洞 ：地球上最人迹罕至之处

仔细听

Blue holes get their name from the color some have when seen from the air.The color is usually a reflection of the sky on the water.But not all of these cave systems have blue surfaces.Some contain dark or muddy water.

蓝洞得名于从空中看时某些洞穴呈现出的颜色。这种颜色通常是天空在水面上的反射。但并不是所有的洞穴系统的表面都是蓝色的。有些洞穴含有黑水或者浑水。

听力破解：But not的发音属于爆破音+[m/n]的组合，这时候前面的爆破音也会失去爆破。

仔细听

Blue holes are the result of erosion in which water break down rock.Rain falling thousands of years ago contained chemicals which slowly wore away at the limestone landmass.These holes later filled with sea water as the sea level changed.The rising and falling of sea levels and the mixture of salt and fresh water further wore away at these cave formations.Blue holes are vertical caves.But they can also have horizontal cave formations that may be hundreds of meters long.

蓝洞是水对岩石侵蚀的结果。几千年前的雨水包含化学成分，慢慢侵蚀着石灰石陆地。这些洞后来在海平面变化时被海水灌满。海平面的升降以及咸淡水的混合进一步侵蚀了这些洞穴的构造。蓝洞是垂直洞穴。但是它们也可以有长达数百米的水平的洞穴构造。

听力破解：limestone中的t的发音[t]发生浊化，读成[d]；hundreds of连读为[′hʌndrədzəv]。

词汇宝典：wore away是wear away的过去式，表示“磨损，衰退，消逝”。

仔细听

These flooded cave systems can be found in the ocean，or they can be found inland.Ocean caves are affected by tides，so they always have water movement.But blue holes on land are very still.They have several layers of water，chemicals，and bacteria.The top layer of fresh water comes from rainfall.This layer acts like a cap on top of the layered mixture，and keeps out oxygen from the atmosphere.The fresh water floats on a denser layer of saltwater.Underneath this is a layer of poisonous hydrogen sulfide，produced by bacteria living in the water.Underneath this layer is anoxic seawater—water that does not contain any oxygen.

这些被淹没的洞穴系统在海洋或内陆都可以找到。海洋洞穴受潮汐影响，经常有水流运动。但是陆上的蓝洞则是静止的。它们有不同的水层、化学成分层和细菌层。最上面的淡水层来自降雨。这一层就像个帽子一样盖在层状混合物的顶上，并隔绝大气中的氧气。淡水漂浮在密度较大的盐水层之上。其下是有毒的硫化氢层，它是由生活在水中的细菌产生的。在这一层下面是缺氧海水——不含任何氧气的水。

听力破解：found in连读，注意其发音和founding的区别。

词汇宝典：still通常做副词，表示“还，更，仍”，在这里做形容词，表示“静止的，寂静的，不动的”，如：Still water runs deep.静水深流/大智若愚。

学着说一说

1.get one's name from得名于……

▶get one's name from 是“得名于……”的意思，如：

Athens gets its name from Athena.雅典得名于雅典娜女神。

▶还有个相似的短语是name after，指“以……命名”，如：

The machine is named after its inventor.这台机器以其发明者命名。

2.wore away磨损；衰退；消逝

▶wore away 是 wear away 的过去式，表示“磨损；衰退；消逝”，如：

Rain and frost are natural agents that wear away rocks.

雨和霜都是磨蚀岩石的自然力。

▶另外，我们知道wear的意思是“穿，戴”，但是它还有个意思是“磨损”，如：

the wear and tear of time岁月的侵蚀

▶习 wear and tear表示“因用久而损坏、损耗”，而不是“穿和眼泪”，如：

The product can stand wear and tear.这款产品经久耐用。

3.act l ike像，表现得像

▶act like 表示“像，表现得像”，如：

She acts like a man while at work.她工作的时候像个男人。

▶act 的常用短语还有：

act as 表示“担任……”，如：

You'll act as the interpreter.你得担任翻译。

act for 表示“代表 ……”，如：During her illness her husband has been acting for her in her business.在她患病期间，她丈夫一直代理她的业务。