Yeah is a State of mind

Youth is not a time of life, it is a state of mind .

年轻不是生命的一个阶段，而是一种思想的状态。

it is not a matter of rosy cheeks,red lips and supple knees,

它无关乎是否拥有莹润的脸颊、火红的嘴唇和柔软的双膝，

it is a matter of the will,

而在于你的所拥有的意志，

a quality of the imagination, vigor of the emotions,

一种创造力和激情，

it is the freshness of the deep springs of life.
他是让蕴藏在生命中的浓浓春意焕发出的勃勃生机。

Youth means a temperamental predominance of courage over timidity. of the appetite for advnture over the love of ease.

年轻意味着勇气会坚定的超越于胆怯之上，意味着对冒险的渴望胜过于贪图安逸，

This often exists in a man of 60 more than a boy of 20.

这样的意志往往更多存在于一个60岁的男人身上，而非体现在一个20岁的大男孩身上。

Nobody grows old merely by a number of years.

对于一个人而言，他变得年老并非仅仅归罪于时间的推移，

We grow old by deserting our ideals.

而是由于我们放弃了我们的理想。

Years may wrinkle the skin, but to give up enthusiasm wrinkles the soul.

时间会在皮肤上雕刻出皱纹，而放弃热情会让我们的灵魂也烙上年轮的痕迹。

worry, fear ,self- distrust bows the heart and turns the spring back to dust.

焦虑、恐惧、畏缩，让我们屈从，让我们的心灵之泉干涸殆尽。
When the aerials are down, and your spirit is covered with snows of cynicism and the ice of pessimism, then you are grown old, even at 20,

当你（和这个世界连接）的天线掉落下来，当你的精神被玩世不恭和悲观失望的冰雪所覆盖的时候，你变老了，尽管也许你只有20岁。

But as long as your arerials are up.

但如果你重新将它立起，

To catch waves of optimism,

去捕捉乐观的电波，

 There is hope you may die young at 80!

即使你在80岁的时候离开这个世界，你依旧是年轻的。

Yeah is a State of mind (do you want to write "youth is a state of mind?")

Youth is not a time of life, 年轻不是生命的一个时间段

it is a state of mind .它是思想的一个阶段

it is not a matter of rosy cheeks,它不是玫瑰色的脸颊

red lips 红唇

 and supple knees,和 柔软的膝盖

it is a matter of the will, 他是有关欲望

a quality of the imagination, 创造能力的大小

vigor of the emotions, 情绪的活力

it is the freshiness of the deep springs of life. （I do not know freshiness mean, doyou want to say freshness? ）
Youth means a temperamental predominace of courage over timidity.年轻就是勇气压倒胆怯的卓越的性情

of the appetite for adventure over the love of ease.对于冒险的渴望超过贪图安逸的欲望

 This often exists in a man of 60 more than a boy of 20. 这常常更多的存在于60岁的人而被不是20岁的孩子身上

Nobody grows old merely by a number of years. 没有人仅仅因为年份这个数字的变化而变老

We grow old by destering our ideals. 我们变老是因为我们不在追求梦想（I can know what you mean,however, I do not know what destering mean? ）
Years may wrinkle the skin, 年代会使我们皮肤覆盖皱纹

but to give up enthusiasm wrinkles the soul.  但是放弃激情会使我们的灵魂起皱

worry, fear ,self- distrust焦虑，害怕，畏缩
 bows the heartand （I can not understand ）turns the spring back to dust. 使青春化为灰烬

When the aerials （what is it mean here ? airplane?）are down,

and your spirit is covered with snows of cynicism and the ice of pessimism, 你的精神被讽刺的雪覆盖，被悲观冰封

then you are grown old, 然后你就老了

even at 20,即使你是20岁

But as long as your arerials are up. 但是当你的 arerials up

To catch weavs（I can not understand） of optimism,抓住乐观主义的 weavs

There is hope you may die young at 80! 希望你到80岁还年轻！（not so sure）

Hope you can use chinese next time!

By the way, l learned many words in your composition,haha~~~

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