在快速变化的市场中，只有不断学习和适应，才能保持竞争力。

The only relationship that can make both partners happy is one in which sentimentality has no place and neither partner makes any claim on the life and freedom of the other.

国家是理性的行为者，在无政府状态的国际体系中寻求最大化其权力和安全。