There are whole catalogs that you go to and buy restriction enzymes.

我们已经可以从整本的目录上,挑选购买限制性内切酶

耶鲁公开课 - 生物医学工程探索课程节选

When I open the blue book, the Yale guideline, the Yale catalog, it's got a page, as you all know, where it says what letter grades mean at Yale.

我打开那本蓝皮书，耶鲁指导手册，耶鲁目录，有这么一页，都见过，讲耶鲁每个评分字母表示什么。

耶鲁公开课 - 死亡课程节选