So the library books are all optional background.

所以图书馆内的书,都是可供选择的背景资料

耶鲁公开课 - 金融市场课程节选

And if you go into the library you could find books on topics that we are discussing here, and you could read on your own.

如果你们进去图书馆，你们可以,找到很多关于我们在这讨论的话题的书，你们可以自己读一读。

麻省理工公开课 - 固态化学导论课程节选

Bad handwriting is the nemesis of historians, But he built a private library, and it wasn't just full of religious books.

难以辨认的字迹毫无疑问是历史学家的噩梦,他建了个私人图书馆,里面装的并不都是宗教书籍

耶鲁公开课 - 欧洲文明课程节选

This is the freedom of thesmorgasbord, of the public library/smorgasbord, or Atticus for that matter, actually, they don't let you eat around the books.

这是自助餐的自由，公众的自由，或是书店和咖啡馆，事实上，他们不允许你在书周围吃东西。

耶鲁公开课 - 弥尔顿课程节选

If you go to the library, they have books.

如果你去图书馆，那儿有书。

麻省理工公开课 - 固态化学导论课程节选