Trace is a type of Return. Return is related to Store. you are likely to find Food in/at/on Store. you are likely to find Food in/at/on Mall. 
Lock can be used for Privacy. Lock is a type of Pass. Pass is a synonym of State. you are likely to find County in/at/on State. 
Trace --IsA--> Return <--RelatedTo--> Store <--AtLocation-- Food --AtLocation--> Mall 
Privacy <--UsedFor-- Lock --IsA--> Pass <--Synonym--> State <--AtLocation-- County 