大家好，请问一下
Webster's New Dictionary of Synonyms: A Dictionary of Discriminated Synonyms
with Antonyms and Analogous and Contrasted Words
使用介绍里，有一句话不了解：
These aims are made practical and easy of attainment by an additional aid
which no work on synonyms has hitherto given the consultant.
which代替aid，但要怎么还原回去呢？
是这样吗？
the aid has hitherto no work on synonyms given the consultant.
关键是，我不知道no work on synonyms代表什么意思 @@a
附上照片图档，供参考。谢谢！
http://i.imgur.com/Kh6SnJm.jpg