adj.年轻的；有青春活力的；年轻人的；(地质学)幼年期的
No one can remain youthful forever. 没有人能永保青春。
His youthful escapades came back to haunt him. 年轻时的胡作非为时常令他感到苦恼。
He was youthful but white-haired. 他虽已白发苍苍,却仍然朝气蓬勃。
If you want to retain youthful vigor,you have to take regular exercise. 如果你想保持青春活力，你就得经常锻炼。
He was full of youthful idealism. 他满脑子都是年轻人的理想主义。
n.年轻
