Lesson 1 How to Make Friends Lesson 2 The Dragon Boat Festival Lesson 3 High Heels Lesson 4 The Best Age to Start a Second Language Lesson 5 Human Migration Lesson 6 Choosing the Right Book Lesson 7 Human Cloning Lesson 8 Encouraging Children's Independence Lesson 9 The Secrets of a Very Long Life Lesson 10 Family Planning Lesson 11 Smoking Lesson 12 Paradise Lost? Lesson 13 Practicing Gratitude Lesson 14 Women's Status Lesson 15 What's the E-mail? Lesson 16 Ad: Prohibited or Not? Lesson 17 Robots Lesson 18 A 13th Century Traveler to China Comes to Light Lesson 19 Solar Power Lesson 20 The Inventions of Thomas Edison