Teenagers reading extra-cursory books can help them expand their knowledge, cultivate their interests and hobbies, and improve their language ability and thinking ability. The following are some types of books suitable for teenagers: 1. Fictions: Reading novels is a good way to expand your vocabulary, cultivate your reading habits, and improve your language skills. The genre of the novel can cover a variety of topics such as science fiction, fantasy, history, love, etc. It is suitable for readers of different ages. 2. Biography: Reading biographies can help you understand the life experiences and achievements of different characters and help you cultivate your own critical thinking and historical awareness. Biography usually covers a variety of topics such as politics, culture, and art. 3. Poetry: Poetry is an art form to express emotions and thoughts, suitable for young readers to appreciate and create. Reading poetry could help them improve their language skills and sense of rhythm. 4. Self-help books: Self-help books can help teenagers understand self-awareness, self-management, and solutions to problems. These books usually cover a variety of topics such as success, psychology, health, finance, etc. 5. Popular science books: popular science books can help young people develop curiosity and thirst for knowledge by understanding various scientific knowledge and phenomena. The popular science books also covered various topics such as physics, chemistry, biology, geography, and so on. Reading extra-cursory books is a good way to improve the overall quality and enrich life experience. Young readers can choose books suitable for themselves according to their interests and needs.