Period is related to Year. Year is a synonym of Class. Class is related to Teaching. Teaching is a type of Doctrine. 
Shortage is a synonym of Deficit. Deficit is the opposite of Profit. Profit is the opposite of Debt. 
Period <--RelatedTo--> Year <--Synonym--> Class <--RelatedTo--> Teaching --IsA--> Doctrine 
Shortage <--Synonym--> Deficit <--Antonym--> Profit <--Antonym--> Debt 