Agreement is related to Accept. Accept is a synonym of Acknowledge. 
Index is a type of Supply. Supply is related to Surprise. Surprise is related to Cause. Cause is the opposite of Prevent. 
Agreement <--RelatedTo--> Accept <--Synonym--> Acknowledge 
Index --IsA--> Supply <--RelatedTo--> Surprise <--RelatedTo--> Cause <--Antonym--> Prevent 