If you opened your speech with a question, Professional speaker Patricia Fripp suggests closing your speech by repeating the same question. The audience will now see that question differently because of what they learned in the presentation. For example, "What is the most important thing in the world? As you now know, it's not what people normally think of. Instead..."
Back again,
Tim Wilson
Professional Speech Coach
Free speaking tips at: http://speakingquicktips.blogspot.com