"Youth is not a time of life. It is a state of mind. It is not a matter of rosy（美好的） cheeks（面颊）, red lips, and supple（柔软的） knees. It is a matter of the will, a quality of the imagination（想象）, a vigor（ 活力） of the emotions. It is the freshness（新鲜） of the deep springs of life. Youth means a temperamental（由气质引起的） predominance（优势） of courage（勇气） over timidity of the appetite. For adventure over the love of ease（容易）.

  This often exists in a man of sixty more than a boy of twenty. Nobody grows old merely（仅仅） by number of years.