Annie DeLoo is a little girl who played the musical instrument known as the Klink in the Jingle Day Pageant. She confided in Mrs. Zabarelli that she had stage fright, but Mrs. Zabarelli gives her some encouraging advice, "We don't know what we can do until we try."
From then on, that phrase became Annie's words of wisdom. As she grew up, Mrs. Zabarelli passed the holiday baton to Annie, and she became the teacher. As an adult, she gave the same wisdom to her student.