Breathholding time for the free diver is highly variable as this is very adaptive. Divers who do this often and train themselves can prolong their dive times considerably.

自由潜水者屏住呼吸的时间大不相同。通过经常做或训练可以显著延长潜水时间。

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It includes nearly 500 positions, including chimney sweep, firefighter,blacksmith,steel worker, diver and metro train operator.

VOA: standard.2009.11.05