她根据作者、年龄和插图画家分别为该书编了索引。She's indexed the book by author, by age, and by illustrator.这个存量巨大的档案室的所有文件都已编了索引，可供研究人员使用。This vast archive has been indexed and made accessible to researchers.在索引中查找。Look it up in the index...
Sawdust was used as a hygienic floor covering.锯屑曾被用来铺在地上保持地面清洁卫生。Food must be prepared in hygienic conditions.食物必须在卫生的环境中制作。It's more hygienic to use disposable paper tissues.使用一次性餐巾纸更为卫生....