A tranquil mind is the source of health.
Words are like keys. If you choose the right ones, they can open any door.
你知道的越多，就越意识到自己不知道的越多。
Sustainability is not an option; it's a necessity for the future of farming.
Every book is a door that opens onto another world, and every reader is a traveler who steps through it.
The use of a program to prove the 4-color theorem will not change mathematics - it merely demonstrates that the theorem, a challenge for a century, is probably not important to mathematics.