Circuit is related to Electricity. Electricity is related to Current. Current is related to Unit. Unit is related to Car. 
Carry is related to Pick. Pick is a type of Remove. Empty is a type of Remove. 
Circuit <--RelatedTo--> Electricity <--RelatedTo--> Current <--RelatedTo--> Unit <--RelatedTo--> Car 
Carry <--RelatedTo--> Pick --IsA--> Remove <--IsA-- Empty 