Train is a synonym of Coach. Coach is related to Stage. Cast entails/necessarily involves Stage. 
Should is related to Regret. Regret is a type of Miss. Miss is related to Lady. Lady is the opposite of Lower. 
Train <--Synonym--> Coach <--RelatedTo--> Stage <--Entails-- Cast 
Should <--RelatedTo--> Regret --IsA--> Miss <--RelatedTo--> Lady <--Antonym--> Lower 