She was four years old.

那时她四岁。

youdao

Lily could swim when she was four years old.

（能力）当莉莉四岁的时候她就会游泳。

youdao

She was unable to speak when she was four years old.

当她四岁的时候她还不会说话。

youdao

She was eighty-four years old. She was buried near the remains of her husband in the state of South Carolina.

VOA: special.2010.08.08

When she was about four years old, she heard her mother struggling to play a piece of music on the piano.

VOA: special.2010.04.09

Other scientists paid Margaret Mead a high honor when she was seventy-four years old.

VOA: special.2010.01.17

She was only four years old.

WHITEHOUSE: President Obama and Vice President Biden Visit Troops at Fort Campbell | The White House

His Charlie was twenty-eight now, so she would have been four years old when he wrote that date.

NEWYORKER: A Beneficiary