Duck is related to Rubber. you are likely to find Rubber in/at/on Classroom. Student can be used for Classroom. 
Fit is related to Health. Health is related to Necessity. Necessity is related to Manner. 
Duck <--RelatedTo--> Rubber --AtLocation--> Classroom <--UsedFor-- Student 
Fit <--RelatedTo--> Health <--RelatedTo--> Necessity <--RelatedTo--> Manner 