Where Did She Get That?

Petra did the funniest thing yesterday. I was sitting at the computer doing some schoolwork and she came into my room.
"Mom, can I watch TV?"
"No."
I went back to my school work, and she went over to my dresser and started messing around, but I wasn't paying very much attention.
"Mom, repeat what I say."
The only way to keep her reasonably entertained so that I can accomplish anything is to play along.
She said, "Mmmm mmmm"
I said, "Mmmm mmmm."

She said, "Mmmm Ahmmm."
I said, "Mmmm Ahmmm."

She said, "Yes!"
I said, "yes."

She said, "No!"
I said, "no."

She said, "I can watch TV!"
I said, "No you caaaan't!"

Lol. As we say about her almost every day, "Where did she get THAT?"