Difficult is a synonym of Hard. Life can be Hard. Sun can be used for Life. Sun is related to Empire. 
Privilege is a synonym of Liberty. Liberty is related to Choice. Choice is a synonym of Option. Preference is a type of Option. 
Difficult <--Synonym--> Hard <--HasProperty-- Life <--UsedFor-- Sun <--RelatedTo--> Empire 
Privilege <--Synonym--> Liberty <--RelatedTo--> Choice <--Synonym--> Option <--IsA-- Preference 