JJ Lin is suffering in D tune. The key is the fixed height of the music, and the key signature is the mark of the key. The sharp and flat marks written behind the opening clef of each line of staff are the key signatures. There are 7 major syllables including sharps, and G major (1 sharps), D major (2 sharps), A major (3 sharps), E major (4 sharps), B major (5 sharps), F sharp major (6 sharps), C sharp major (7 sharps).