you are likely to find Curtain in/at/on Opera. Curtain can be used for Blind. 
Comment is a synonym of Remark. Remark is related to Answer. Answer is related to Response. Response is related to Denial. 
Opera <--AtLocation-- Curtain --UsedFor--> Blind 
Comment <--Synonym--> Remark <--RelatedTo--> Answer <--RelatedTo--> Response <--RelatedTo--> Denial 