区别就是两者意思是不一样，具体的不同如下

library中文意思是n. 图书馆，藏书楼（书、激光唱片等的）私人收藏书房，书斋文库，系列丛书（激光唱片集，成套录像等）软件库

The library is all on one level.

wallpaper中文意思是n. [建] 壁纸，墙纸

We were going to wallpaper that room anyway.