Contribute is a synonym of Assist. Assist is related to Support. Support is a type of Activity. Operation is a type of Activity. 
Stroke is related to Face. Face is a type of Disclose. Disclose is a synonym of Uncover. 
Contribute <--Synonym--> Assist <--RelatedTo--> Support --IsA--> Activity <--IsA-- Operation 
Stroke <--RelatedTo--> Face --IsA--> Disclose <--Synonym--> Uncover 