Doll is related to Little. Little is a synonym of Weak. Weak is a synonym of Shallow. 
Oil is related to Drill. Drill is related to Worker. Worker is derived from Work. Work is related to Van. 
Doll <--RelatedTo--> Little <--Synonym--> Weak <--Synonym--> Shallow 
Oil <--RelatedTo--> Drill <--RelatedTo--> Worker --DerivedFrom--> Work <--RelatedTo--> Van 