Apology is related to Say. Say is a type of Express. 
one thing you do when you Climb is Grab. Climb is related to Vertical. Vertical is related to Low. Low is a form of Laugh. 
Apology <--RelatedTo--> Say --IsA--> Express 
Grab <--HasSubevent-- Climb <--RelatedTo--> Vertical <--RelatedTo--> Low --FormOf--> Laugh 