I am trying to learn at a time solfeggio and piano with your lessons, Mr Hoffman, I am thus a newbie in both. Further more English is not my native language, and i do my best to be clear. I confess that I am a bit confused when I observe, in this lesson, that the position on the big staff of DO/C has moved. In the first videos, C was on the ledger line (see Unit 2, Lesson 21) and I had started to memorize the whole whole staff with this layout. In this video (unit 2, lesson 35), where we have to play in SOL/G key), DO/C has suddenly took the place of previous SOL/G on the staff. My question is : does the DO/C (and consequently all the other notes ) change position on the staff each time we play in another key? Is it movable each time? If so, how to know it, read and memorize all these changes? It gets complex and confusing. Thanks for your answer, Mr Hoffman.