This question involved the theme and plot of novels, movies, games, and other creative fields. If it was a sci-fi movie, there might be a scene where a person was trapped in another world or left alone in a strange place. In reality, if a person was left alone in the world, he might face many difficulties and challenges. He needed to find food and water, protect himself from beasts and diseases, and deal with threats from other humans such as robbery or attack. In such a situation, the person may need to develop their skills and knowledge to survive. He might look for other humans to communicate and learn new skills and knowledge to better adapt to this unfamiliar environment. If a person is left alone in the world, he may experience many difficulties and challenges, but he can also develop his skills and knowledge to become an independent and powerful individual.