Most of the earth is made up of water, but human beings come from the primitive ocean. Human beings are the children of the ocean. For the exploration of the ocean, human beings have never stopped their steps, and they are constantly challenging themselves through the ocean.

There is a life rule in diving: one third of the oxygen used in diving is used for exploration, one third for return and one third for special situations.

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In the field of diving, [freshwater cave diving] well embodies the rules of life of this day.

The freshwater cave diving is very challenging. The freshwater caves challenged by divers are all complex caves with caster landform, and the interior of the caves is very circuitous.

There will be accidents at any time when diving in a fresh water cave, so divers will fix a nylon guide line when entering the cave.
In diving, the guide line is called "lifeline". The existence of the guide line is an important factor to decide whether the diver can return to the starting point. If the guide line breaks or falls off, it will directly threaten the life of divers.

Freshwater cave diving requires divers to have rich diving experience and certain knowledge of geography and geomorphology. Taking part in this sport can sometimes be called "nine dead", after all, freshwater caves are complex and changeable.

In addition to challenging themselves, people who take part in freshwater cave diving enjoy the beauty of freshwater caves.

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地球大部分都是由水组成的，而人类却来源于原始海洋，人类是大海的孩子。对于海洋的探索，人类从没有停止过步伐，人类也通过海洋不断地挑战着自己。

在潜水领域有这样一条生命规则：潜水所使用的氧气，1/3用于探险，1/3的氧气用于返回，1/3用于应对特殊情况。

在潜水领域，【淡水洞穴潜水】很好地体现了这一天生命规则。

淡水洞穴潜水非常的具有挑战性，潜水员所挑战的淡水洞穴都为具有卡斯特地貌的复杂洞穴，洞穴内部非常的迂回。

进行淡水洞穴潜水随时都会发生意外，所以潜水员在进入洞穴的时候都会固定一条尼龙线材质的引导线。

在潜水运动中，引导线被称为“生命线”，引导线的存在是决定潜水员能否返回起点的重要因素。如果引导线断裂或者脱落会直接威胁到潜水员的生命。

淡水洞穴潜水需要潜水员有丰富的潜水经验以及一定的地理地貌知识。参加这项运动有时候可以说是“九死一生”，毕竟淡水洞穴复杂多变。

参加淡水洞穴潜水的人除了挑战自我之外就是欣赏淡水洞穴的美丽。

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