young/adolescent/juvenile/youthful.导航词义：年轻的，年幼的

1. young:adj. 年幼的，年轻的.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。

2. adolescent:adj. 青春期的，青少年的.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。

3. juvenile:adj. 少年的；;幼稚的.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。

4. youthful:adj. 年轻的，年轻人的.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。

全部

1·He was full of youthful idealism.

他满脑子都是年轻人的理想主义。《牛津词典》

2·She's a very youthful 65.

她65岁了，但显得非常年轻。《牛津词典》

3·I'm a very youthful 50.

我是个显得很年轻的50岁的人。《柯林斯英汉双解大词典》

4·We can excuse his behaviour as youthful exuberance.

年轻人精力旺盛，所以他的行为我们也能原谅。《牛津词典》

5·Her energy and youthful good looks belie her 65 years.

她的活力与年轻美貌使人看不出她有65岁了。《牛津词典》

6·Youthful idealism is often courageous, and no one likes to give up dreams.

年轻的理想主义往往是勇敢的，并且没人愿意放弃梦想。

7·He said Washington believed the penalty was excessive for a youthful non-violent offender.

他说，华盛顿认为对一个年轻的非暴力罪犯的处罚过于严重了。

8·The youthful narrator remarks that everybody suspects himself of having at least one of the cardinal virtues.

年轻的叙述者说，每个人都怀疑自己至少有一种主要的美德。

9·In government laboratories and elsewhere, scientists are seeking a drug able to prolong life and youthful vigor.

在政府实验室和其他地方，科学家们正在寻找一种能够延长寿命、让人保持年轻活力的药物。

10·The skin loses its youthful bloom.

皮肤失去了年轻时的红润。《柯林斯英汉双解大词典》