Fear is related to Related. Related is related to Reading. Reading is related to Process. Phenomenon is a type of Process. 
Difficulty is a synonym of Obstacle. Obstacle is related to Course. Course is related to Literature. 
Fear <--RelatedTo--> Related <--RelatedTo--> Reading <--RelatedTo--> Process <--IsA-- Phenomenon 
Difficulty <--Synonym--> Obstacle <--RelatedTo--> Course <--RelatedTo--> Literature 