Chief is etymologically related to Head. Head is related to Shade. you are likely to find Shade in/at/on Bridge. you are likely to find Echo in/at/on Bridge. 
Complicated is related to Theory. Theory is a type of Belief. Belief is related to Religion. 
Chief --EtymologicallyRelatedTo--> Head <--RelatedTo--> Shade --AtLocation--> Bridge <--AtLocation-- Echo 
Complicated <--RelatedTo--> Theory --IsA--> Belief <--RelatedTo--> Religion 