Her earliest memory is of singing at the age of four to wounded soldiers.

她最早的记忆是在4岁时为受伤的士兵唱歌。

《柯林斯英汉双解大词典》

At the age of four, she began to learn how to play the guitar.

四岁时，她开始学习弹吉他。

youdao

At the age of four, Rostropovich learned the piano with his mother, Sofiya Nikolaevna Fedotova, a talented pianist.

四岁时，罗斯特罗波维奇和母亲索菲娅·尼古拉耶夫娜·费多托娃一起学习钢琴，索菲娅是一位才华横溢的钢琴家。

youdao

She died at the age of four. Bucky Fuller blamed himself, although he had done everything he could to save her.

VOA: special.2010.05.30

At the age of four, Mary began walking to the nearest school several kilometers away.

VOA: special.2010.06.27

She taught herself to play the piano at the age of four.

VOA: special.2009.02.27

Janet Valentine's daughter Kayleigh died nine years ago at the age of four months.

BBC: News Online

Bloom first performed before an audience on the stage of the Marlowe Theatre in Canterbury at the age of four.

BBC: Orlando Bloom backs East Kent City of Culture bid

He was born into a brass band family and was taught to play the cornet at the age of four by his father.

BBC: James Bond trumpeter Derek Watkins dies