and prevented them from drying out. 并防止水分流失

57. Relatives of the trilobites,
    它们是三叶虫的亲戚
58. their hard exoskeletons had served as useful armor underwater.
    坚硬的外骨骼在水下是有用的护甲
59. On land, that armor supported them
    在陆地上 这护甲支撑着它们
60. and prevented them from drying out.
    并防止水分流失
61. They could also breathe through this tough exterior.
    它们也可以通过这坚硬的外壳呼吸
62. And with oxygen levels 60% higher than they are today,
    当时的氧气水平比今天高60%
63. some grew to be giants.
    有一些节肢动物长得异常巨大

来自《我们星球上的生命 第一季 第三集 Life on Our Planet S01E03 入侵大地》第 60 行