Hard is related to Effort. Trouble is a type of Effort. Trouble is related to School. 
Recent is a different concept from Old. Old is related to Steam. Steam is a different concept from Electric. 
Hard <--RelatedTo--> Effort <--IsA-- Trouble <--RelatedTo--> School 
Recent <--DistinctFrom--> Old <--RelatedTo--> Steam <--DistinctFrom--> Electric 