530 million years ago, 5.3亿年前

77. they were able to separate into layers of individuals,
    但还是能够分离成数层个体层
78. that then broke free.
    然后独♥立♥出来
79. Jellyfish.
    那就是水母
80. 530 million years ago,
    5.3亿年前
81. they were the very first animals to escape the seafloor and swim.
    它们是第一种从海底逃离 并开始游泳的生物
82. But predators were already everywhere.
    但是捕食者已经无处不在
83. Armed with venomous harpoons,
    这些海葵装备有带毒的鱼叉

来自《我们星球上的生命 第一季 第二集 Life on Our Planet S01E02 第一前线》第 80 行