- Many couldn't digest grass
许多无法消化草的动物 - and soon went extinct.
很快灭绝 - Twenty million years later,
2000万年之后 - and today's grazing mammals
今天的食草哺乳动物 - remain locked in an arms race with this green invader.
仍在与这绿色入侵者 继续展开军备竞赛 - They have evolved a whole swathe of game-changing adaptations.
它们进化出了 一系列极为重要的适应性 - Specialized teeth,
经过特别加强的牙齿