占据地球３／４面积的海洋对于生活在陆地上的人们来说是那么的深奥和神秘，自古以来，人们都一直向往去探索那个深深的未知世界。由于肺活量有限，人们在潜水时会将一个桶扣在头上，这样通过呼吸桶中压缩的空气可以潜得时间更长些。但是这样人仍无法在水下自由活动，于是人们? The oceans, which occupy three-quarters of the planet, are so mysterious and mysterious to those living on land that since ancient times, people have been longing for the deep, unknown world. Due to the limited lung capacity, people buckle their head with a bucket while diving, which can allow for longer periods of time through the compressed air in the breathing barrel. However, such people still can not move freely under the water, so people?