Cost is related to Bill. Bill is related to Expensive. Expensive is related to Crystal. 
you are likely to find Beam in/at/on Roof. you are likely to find Roof in/at/on Garage. 
Cost <--RelatedTo--> Bill <--RelatedTo--> Expensive <--RelatedTo--> Crystal 
Beam --AtLocation--> Roof --AtLocation--> Garage 