听力原文

More than a hundred fishermen make their living from the lake. Its mineral-rich waters are highly productive, and there are nets everywhere.
上百渔夫依靠这个水质富矿的高产湖泊为生，并在此布下天罗地网。
The next morning, Geng returns with his son to collect his catch. At first sight, it looks disappointing.
第二天清早老耿和他的儿子回来收获他们猎物。乍看之下收获平平。
Tiny fishes, lots of shrimps, and some wriggling bugs. Geng doesn't seem too downhearted. The larger fish are kept alive, the only way they'll stay fresh in the heat.
小鱼，虾米，和扭个不停的虫子。然而老耿看上去来并不那么消沉。大鱼被保持存活，这是唯一在酷暑下保鲜的办法。
Surprisingly, some of the bugs are also singled out for special treatment. They're the young stage of dragonflies, predators that feed on worms and tadpoles.
令人吃惊的是，一些虫子也被专门挑捡出来。它们是蜻蜓的幼虫。以蠕虫和蝌蚪为食的掠食者。
Nowhere else in the world are dragonfly nymphs harvested like this.
这里是世界上蜻蜓卵收获最丰的地方。

重点讲解

重点讲解：
1. at first sigh
乍一看；一见之下；初看时；
eg. It promised to be a more difficult undertaking than might appear at first sight.
那项任务可能比乍看之下还要困难。
eg. At first sight it resembles a traditional village of two-storeyed, balconied houses, set among well-tended gardens.
乍一看，它就像个传统的村庄：带阳台的两层楼房坐落于精心照料的花园中。
2. single out
单独挑出；特别选出；
eg. His immediate superior has singled him out for a special mention...
他的顶头上司特别提到了他。
eg. We wanted to single out the main threat to civilisation.
我们想特别指出威胁文明的主要因素。
3. feed on
用……喂养； 靠吃……过活；
eg. These larvae feed on planktonic algae.
这些幼虫以浮游海藻为食。
eg. In flat open country there is plenty of grass for the cattle to feed on.
在开阔平坦的地区有大量的青草供牛群食用。