Person does not want (to) Difficulty. Person wants (to) Mobile. Mobile is related to Cell. Cell is the opposite of Room. 
Green is related to Lawn. you are likely to find Shit in/at/on Lawn. 
Difficulty <--NotDesires-- Person --Desires--> Mobile <--RelatedTo--> Cell <--Antonym--> Room 
Green <--RelatedTo--> Lawn <--AtLocation-- Shit 