外科医生成功地给一个四岁的男孩移植了肝脏。

Surgeons have successfully transplanted a liver into a four-year-old boy.

《牛津词典》

四岁的儿子默默地看着这一切。

The four-year-old son watched it all in silence.

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他四岁的时候生活很幸福。他不擅长弹钢琴。

He lived a happy life at the age of 4. He was not good at playing the piano.

youdao

There's sort of a period around the age of four, four and a half, where kids make the transition from failure to success.

儿童在大约四岁四岁半时,会发生从失败向成功的转变

耶鲁公开课 - 心理学导论课程节选

Oh, that goes actually way back time when we were like little kids like, four years old,

哦，那其实要追溯到我们是小孩子的时候了，四岁的时候，

和朋友一起逛洛杉矶 - SpeakingMax英语口语达人

Typically--I don't know for those particular children, but typically on those tasks three-year-olds and young four-year-olds tend to fail, and around the age of four or five kids tend to succeed.

我不太了解那些特定儿童的情况,但一般来讲,三岁和刚进入四岁的儿童,通常会在这些任务中失败,而四岁或是五岁左右的儿童则通常会成功

耶鲁公开课 - 心理学导论课程节选