You have begot me, bred me, loved me: I Return those duties back as are right fit, Obey you, love you, and most honour you.
Make up your mind to act decidedly and take the consequences. No good is ever done in this world by hesitation.  
模型的目的是足够简单以便理解和使用,但又足够复杂以捕捉系统的基本特征。
货币政策是强有力的稳定工具,但它无法同时实现两个独立的目标。