Form is related to Sheet. Board is a type of Sheet. Board is related to Risk. 
Electricity can be Powerful. Powerful is the opposite of Vulnerable. Vulnerable is the opposite of Immune. Carrier is a type of Immune. 
Form <--RelatedTo--> Sheet <--IsA-- Board <--RelatedTo--> Risk 
Electricity --HasProperty--> Powerful <--Antonym--> Vulnerable <--Antonym--> Immune <--IsA-- Carrier 