Sentence:  Everyone is ambivalent about his profession , if he has practised it long enough , but there were still moments when he loved the stage and all those unseen people out there , who might cheer you or boo you , but that <WSD>was</WSD> largely , though not entirely , up to you . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)