Lemon is a synonym of Bomb. you are likely to find Bomb in/at/on Aircraft. you are likely to find Aircraft in/at/on Sky. Sky is related to Buy. 
Drop is related to Zone. Island is a type of Zone. 
Lemon <--Synonym--> Bomb --AtLocation--> Aircraft --AtLocation--> Sky <--RelatedTo--> Buy 
Drop <--RelatedTo--> Zone <--IsA-- Island 