Long is similar to Stretch. Stretch is a synonym of Patch. Patch is related to Cover. Cover is a synonym of Treat. 
Known is the opposite of Unknown. Unknown is a different concept from Familiar. Familiar is related to Similar. Similar is a synonym of Comparable. 
Long <--SimilarTo--> Stretch <--Synonym--> Patch <--RelatedTo--> Cover <--Synonym--> Treat 
Known <--Antonym--> Unknown <--DistinctFrom--> Familiar <--RelatedTo--> Similar <--Synonym--> Comparable 