你必须准备好受苦并享受这种痛苦。
"You have to be ready to suffer and enjoy the suffering."
任何圆的周长与其直径的比率小于3 1/7但大于3 10/71。
The beauty of topological insulators lies in their robustness; their surface states are protected by symmetry and topology, making them immune to certain types of disorder.