Bulk is a synonym of Volume. Volume is a synonym of Space. Space is related to Article. 
Soften is a synonym of Yield. Fall is a type of Yield. Fall is related to Go. 
Bulk <--Synonym--> Volume <--Synonym--> Space <--RelatedTo--> Article 
Soften <--Synonym--> Yield <--IsA-- Fall <--RelatedTo--> Go 