Grade is a synonym of Level. Level is related to Easy. Easy is a synonym of Fast. 
Recession is a synonym of Return. Return is related to Payment. Payment is related to Transaction. Transaction is related to Buy. 
Grade <--Synonym--> Level <--RelatedTo--> Easy <--Synonym--> Fast 
Recession <--Synonym--> Return <--RelatedTo--> Payment <--RelatedTo--> Transaction <--RelatedTo--> Buy 