 The structure of a lesson. We're going to learn three things about the structure of a lesson. How many parts a lesson has, the function of each part, and how much time each part takes. How many parts does a lesson have? One, two, three! The functions of a lesson's three parts are introduction, new information, and review. Introduction, new information, and review. Here is how much time each part takes. Introduction one-fifth, new information three-fifths, and review one-fifth. So we learned three things about the structure of a lesson. A lesson has three parts, introduction, new information, and review. The introduction is one-fifth, new information is three-fifths, and the review is one-fifth. Oh, and one more thing we learned. Watch out for squirrels!