1.
My father worked until he was 65 years old
My father stopped working because he was 65 years old.
My father stopped working when he was 65 years old.
2.
Mrs Peterson was looking very young until she was 45 years old.
Mrs Peterson was looking very young when she was 45 years old.
Mrs Peterson was looking very young because she was 45 years old.
3.
He didn't go to school yesterday because he was ill.
He was ill when he didn't go to school yesterday.
He went to school until he wasn't ill.
