Bull is a synonym of Cop. Cop is a synonym of Police. Police can Arrest. Arrest is a synonym of Check. 
Task is related to Requirement. Requirement is related to Do. Do is the opposite of Possible. 
Bull <--Synonym--> Cop <--Synonym--> Police --CapableOf--> Arrest <--Synonym--> Check 
Task <--RelatedTo--> Requirement <--RelatedTo--> Do <--Antonym--> Possible 