One More?

I took Grace to my office the other day and her friend Mrs. Doris gave her a small bag of cookies. On the way home, I asked Grace if she would share with me. She said yes and handed me a cookie. I asked her if she would share again and she said "one more." Once she handed it to me, she said "you done." I was most surprised, especially given that Grace pretends not to know the meaning of "one more" when she asks me for anything. True to her words, Grace refused to give me any more cookies, despite my repeated requests!