3 sentences

1. 皮肤的最外层由上皮细胞组成。

   pí​fū de zuì wài​céng yóu shàng​pí xì​bāo zǔ​chéng.

   The outermost layer of the skin is composed of epithelial cells.

   Source: Dong Chinese Dictionary

2. 地壳是地球最外层的固体部分。

   dì qiào shì dì​qiú zuì wài​céng de gù​tǐ bù​fen.

   The Earth's crust is the outermost solid part of the Earth.

   Source: Dong Chinese Dictionary

3. 他熟练地把地图折叠好，放进了登山包最外层的口袋。

   tā shú​liàn de bǎ dì​tú zhé​dié hǎo, fàng​jìn le dēng​shān​bāo zuì wài​céng de kǒu​dài.

   He skillfully folded the map and put it into the outermost pocket of his hiking backpack.

   Source: Dong Chinese Dictionary