Known is related to Introduce. Introduce is related to Action. Action is related to March. 
Acid can be Dangerous. Dangerous is a synonym of Extreme. Extreme is a synonym of Strong. Strong is related to Metal. 
Known <--RelatedTo--> Introduce <--RelatedTo--> Action <--RelatedTo--> March 
Acid --HasProperty--> Dangerous <--Synonym--> Extreme <--Synonym--> Strong <--RelatedTo--> Metal 