youthful
单词辨析：
指人、动植物幼小、未成熟的。
young animals/children/trees
幼畜/幼儿/小树
The young seedlings grow very fast.
秧苗长得很快。
The young lion stood beside its mother.
小狮子站在母狮的身旁。
He is too young to join the army.
他年龄太小，还不能参军。
指介于儿童和成年人之间的，强调不成熟、叛逆等特点，无比较级。
adolescent attitudes/boys/crises
青春期心态/男孩/危机
Man is still only adolescent.
人类还只是处于青少年时期。
His remarks about the matter struck me as being a bit adolescent.
他对此事的意见让我觉得有点幼稚。
作“少年的”解时，系法律术语，只作定语；作“幼稚的”解时，强调不成熟的。
a juvenile criminal/offender
少年犯
a very juvenile sense of humor
很幼稚的幽默感
Deak is an expert in juvenile delinquency.
迪克是研究青少年犯罪的专家。
The mother is tolerant of her son's juvenile behaviour.
母亲对儿子的幼稚行为非常宽容。
指为年轻人所特有的或看上去年轻的。
youthful enthusiasm/rebellion/vigour
年轻人的热情/叛逆/活力
The photo shows a youthful, sweet Emma.
照片里的埃玛年轻而甜美。
She is over 60 but has a youthful complexion.
她已经年过六旬，但面容依然姣好。
No one can remain youthful forever.
没有人能永葆青春。
相关例句：
It will limber up your spine and keep it in a flexible and youthful condition.
这个练习活动了你的脊椎使其保持弹性和青春的状态。
Gary Glitter, 48, revealed the secret of his youthful looks.
48岁的加里·格利特透露了他青春永驻的秘密。
And his youthful optimism could work at home too.
他的年青和乐观对其家乡也起作用。
The youthful vigor that fills his bones will lie with him in the dust.
他的骨头虽然有青年之力，却要和他一同躺卧在尘土中。
The skin loses its youthful bloom.
皮肤失去了年轻时的光泽。
But I wanted Harry Winston Men to be cool and youthful rather than nostalgic.
但我想让Harry Winston男士系列富有酷和年轻的气息，而不是怀旧。