台湾籍旅美老师今天交给我们的句子是：

This combination of mucus, oil, skin cells and other debris in your eye serves as a protective shield and allows the eye to function properly. So let's get technical for a second: the eyes of mammals are covered by a multi-layer film that helps them do what they're supposed to do.
你眼睛中这个掺杂了黏液、油脂、皮肤细胞和其他残留物质的混合体主要是做为防护用，好让眼睛可以正常运作。因此我们来说点专业的，就是：哺乳类动物的眼睛表面都覆盖着一个多层的薄膜来协助眼睛发挥其应有的功能。

学习重点：

1.combination 结合(体)
combination (n.) 结合(体)
combine (v.) 结合

2.mucus 黏液
mucus (n.) 黏液

3.debris 残骸、瓦砾
debris (n.) 残骸、瓦砾

4.shield 盾牌、保护者
shield (n.) 盾牌、保护者

5.mammal 哺乳动物
mammal (n.) 哺乳动物
reptile (n.) 爬虫类