you are likely to find Human in/at/on Workplace. you are likely to find Union in/at/on Workplace. Union is related to Group. Group is related to Fruit. 
Classroom can be used for Teach. Teach is related to Explain. Explain is related to Justify. 
Human --AtLocation--> Workplace <--AtLocation-- Union <--RelatedTo--> Group <--RelatedTo--> Fruit 
Classroom --UsedFor--> Teach <--RelatedTo--> Explain <--RelatedTo--> Justify 