Happen is related to Impossible. Impossible is the opposite of Certain. Certain is related to Know. Know is a type of Remember. 
Count is a synonym of Consider. Consider is related to Action. Action is related to Learning. 
Happen <--RelatedTo--> Impossible <--Antonym--> Certain <--RelatedTo--> Know --IsA--> Remember 
Count <--Synonym--> Consider <--RelatedTo--> Action <--RelatedTo--> Learning 