朝气蓬勃的英文：
[Literal Meaning]
spirit/vigorous
to be full of vigor and vitality

[解释]
朝：早上；蓬勃：旺盛的样子。形容充满了生命和活力。

[Explanation]
vigorous and energetic

[例子]
在五十年代，人们对新生活充满了渴望，整个社会也朝气蓬勃。

[Example]
In the 50s, people were full of hope toward a new life and the whole society appeared vigorous and energetic.

[英文等价词]
new lease of life
full of energy
spirited

Young people are vigorous and vital.
年轻人朝气蓬勃。

She was bouncy and full of energy.
她朝气蓬勃，充满活力。

They are in their very first youth, full of youthful spirit.
他们青春年少，朝气蓬勃。

Young people are full of vigour and vitality, like the sun at eight or nine in the morning
青年人朝气蓬勃, 好像早晨八、九点钟的太阳。

The presence of the new students lent a vigorous atmosphere to the campus.
新同学的到来给校园增添了朝气蓬勃的气息。

He beat rhythm with his fork against a bottle, singing in a youthful soprano.
他用餐叉敲着酒瓶打拍子，用朝气蓬勃的高音唱起来。

This kind of freely movable body-building equipment can make the young even vigorous and vital and the old youthful.
这类健身器具，活动自如，使青年人更朝气蓬勃，使老年人青春焕发。

The speaker, a large vigorous young man, came bounding down the aisle and up onto the stage
发言者是一个身材魁梧朝气蓬勃的年轻人，他边跑边跳地走过过道，跃上讲台。

A European writer would not, I suspect, feel able to sound so auroral a note
我想一个欧洲作家就不会说出这种朝气蓬勃的话

And when he had gone, she would return to her books with a keener zest and fresh store of energy
他离开之后她再回到书本，钻研起来便更加精力旺盛、朝气蓬勃。