Before revision: wrote "In order to achieve good consistent indexing, the indexer must have a through appreciation of the structure of the subject and the nature of the contribution that the document is making to the advancement of knowledge within a particular discipline".
After revision: wrote "In order to achieve good consistent indexing, the indexer must have a thorough appreciation of the structure of the subject and the nature of the contribution that the document is making to the advancement of knowledge within a particular discipline".