Roves had held a senior position in the Navy before taking office. One of his good friends asked him about the Navy's plan to establish a submarine base on an island. Roosevelt looked around mysteriously and asked in a low voice. "Can you keep it a secret?" "Of course I can!" The friend was very sure. "So," Roosevelt said with a smile, "I can too. ". This text tells us:. ['Detours can also serve the purpose.', 'Humor can subtly solve problems.', 'Adherence to principles and flexibility are not contradictory.', "Don't do anything to others."]