Most early mammals didn't have armor or size to protect them... 多数早期哺乳动物 没有护甲来保护它们
Once upon a time, plants relied solely on wind or water to spread their pollen... 过去植物仅依靠风或水来传播花粉
It'll be seven or eight years of hiding in trees 它要在树上躲七、八年
or even awareness of the threat it poses. 甚至无法意识到对方所带来的威胁
have had little competition or predators, 几乎没有竞争对手和捕食者