Happen is related to Allow. Allow is related to Like. Like is related to Department. 
Enthusiasm is related to Ambition. Ambition would make you want to Study. Study is related to Course. 
Happen <--RelatedTo--> Allow <--RelatedTo--> Like <--RelatedTo--> Department 
Enthusiasm <--RelatedTo--> Ambition --CausesDesire--> Study <--RelatedTo--> Course 