1. The term "Four Ancient Civilizations" refers to ancient China, ancient India, ancient Egypt, and Babylonia. Coined by Liang Qichao, this concept designates the four earliest centers of civilization on Earth.2. This classification is primarily popular in China and has not been widely accepted by the global historical community. It represents only the central parts of the origins of civilization and lacks universality.3. The Four Ancient Civilizations actually correspond to the four major centers of world civilization, referring to the Mesopotamian, ancient Egyptian, ancient Indian, and Chinese civilizations. However, the Aegean civilization, which emerged around the same time, was not included.4. The significance of the Four Ancient Civilizations lies not in their chronological order but in their role as the birthplaces of modern human civilization. These civilizations have contributed to today's world in terms of philosophy, science, literature, art, and more.5. All four ancient civilizations were established near easily habitable river valleys and plains, such as the Tigris and Euphrates rivers, the Nile, the Yellow and Yangtze rivers, and the Indus and Ganges river basins.