Extend is a type of Straighten. Extend is the opposite of Close. Button is a type of Close. Button is related to Enter. 
Bloody is related to War. you are likely to find Pistol in/at/on War. Kill requires Pistol. Kill is the opposite of Save. 
Straighten <--IsA-- Extend <--Antonym--> Close <--IsA-- Button <--RelatedTo--> Enter 
Bloody <--RelatedTo--> War <--AtLocation-- Pistol <--HasPrerequisite-- Kill <--Antonym--> Save 