Topology is the study of the properties of a figure that are unchanged by any deformation.
应该忧虑的是自身不好，而不该忧虑别人不了解自己。《老子》中说“知人者智也，自知者明也。”人生要多些反思，也要多些扪心自问，看清自己更重要。
Success is not final, failure is not fatal: It is the courage to continue that counts.
"To live is the rarest thing in the world. Most people exist, that is all."