Reader is a type of Textbook. Textbook is a type of Book. Fall is a type of Book. Fall is related to Sky. 
Alone is related to Only. Only is related to Exact. Exact is a synonym of True. True is similar to Sure. 
Reader --IsA--> Textbook --IsA--> Book <--IsA-- Fall <--RelatedTo--> Sky 
Alone <--RelatedTo--> Only <--RelatedTo--> Exact <--Synonym--> True <--SimilarTo--> Sure 