Ocean can be used for Fishing. Fishing can be used for Competition. Tie is a type of Competition. Tie is a synonym of Link. 
Explain is related to Teaching. Teaching is related to School. School is related to Elementary. Elementary is related to Primary. 
Ocean --UsedFor--> Fishing --UsedFor--> Competition <--IsA-- Tie <--Synonym--> Link 
Explain <--RelatedTo--> Teaching <--RelatedTo--> School <--RelatedTo--> Elementary <--RelatedTo--> Primary 