Professor is a type of Book. Cat is a type of Book. you are likely to find Cat in/at/on Flat. Flat is the opposite of Rough. 
Greek is related to Empire. Empire is related to Region. Region is a synonym of Domain. Domain is a synonym of Land. 
Professor --IsA--> Book <--IsA-- Cat --AtLocation--> Flat <--Antonym--> Rough 
Greek <--RelatedTo--> Empire <--RelatedTo--> Region <--Synonym--> Domain <--Synonym--> Land 