The Cambrian explosion Diversification变化；多样化We encourage persification in the school system. 我们鼓励办学模式有多元化的发展。
Multicellular 多细胞的What genetic change allowed multicellular animals to come into existence remains obscure. 什么样的遗传突变产生了多细胞动物还不清楚。
That makes up multicellular organisms. 这构成多细胞生物。
Fossilize 使成化石；僵化
The most important parts， the flowers， rarely fossilize. 最重要的部分，即花朵，很少成为化石。
The little animals fossilized and are now embedded in the limestone. 这个小动物变成化石后并嵌入在石灰石里。
Needs change while policies fossilize. 需要发生改变，但是政策僵化不变。
Discourage 使气馁He is easily discouraged by difficulties and obstacles. 他遇到困难和阻碍就容易泄气。
Decomposition 分解；腐烂Warmer weather meant the decomposition of the corpse. 天气变暖会使尸体腐烂。