문법 좀 제발 살려줘ㅠㅠㅠㅠ

"My secret is hidden within me; (my name no one shall know.)" Those are the words, roughly translated, from the famous Puccini aria Nessun Dorma. You have probably heard Luciano Pavarotti sing it once or twice. But it has never had so much meaning (as it did on a stage in Great Britian, being sung by a mobile phone salesman named Paul Potts.)  

저기 괄호 부분 문법구조가 이해가 안가... 특히 두번째 괄호에서 as가 무슨 뜻으로 쓰이고 it이 뜻하는 건 뭐고 did는 뭘 의미하고 being sung이 갑자기 왜 나오는지ㅠㅠㅠㅠ