Grass is a type of Unfold. Unfold is a synonym of Spread. Cancer can Spread. 
Sum is a synonym of Essence. Essence is related to Oil. Oil is related to Controversy. Controversial is derived from Controversy. 
Grass --IsA--> Unfold <--Synonym--> Spread <--CapableOf-- Cancer 
Sum <--Synonym--> Essence <--RelatedTo--> Oil <--RelatedTo--> Controversy <--DerivedFrom-- Controversial 