木质素

例句：

1. 1.The wood is made up of different types of lignin and cellulose.
   木材由不同类型的木质素和纤维素组成。
2. 2. The process of turning wood into paper involves removing the lignin and leaving only the cellulose.
   将木材转化为纸张的过程涉及去除木质素，只留下纤维素。
3. 3. The lignin in wood acts as a protective layer against decay.
   木材中的木质素作为保护层防止腐烂。