I'm learning Beethoven Sonata in G op49 no2. In measure 109 (as well as other places but i am learning the piece out of order) there is a trill in the right hand, the note A with the letters Tr above it. So far i have been learning pieces that give you notation at the bottom of the page on how to play trills, what notes and rhythm to use. When i see the Tr is there a standard way to play it? Right now i've been playing it B-A-G-A and the second A lands on the 3rd beat in the measure. Like i said, i don't know if this is the correct way to do this or if there is a standard way.