适应是理解行为的关键。
"Adaptation is the key to understanding behavior."
Treating a person to a meal never fails， and is so easy to do. It’s powerful with old friends and a great way to make new friends.
The metropolis exacts from man as a discriminating creature a different amount of consciousness than does rural life.
乐观主义者认为这是所有可能世界中最好的一个。悲观主义者知道确实如此。