Examples

由童年而少年，而壮年

from childhood to teenage, then to middle age → 而

他才华横溢，却在壮年暴病而亡，真是天妒英才。 → 暴病

这家伙正值壮年, 却整天躺在家里, 真是个懒鬼！

He is such a lazy bum that he stays home every day, though he is in the prime of life. → 懒鬼

由童年而少年、而壮年 → 而

壮年是心劲正盛的时候。 → 心劲

I never think of summer but I think of childhood.

每当我想起壮年，我就想起了童年。 → but

in the prime of life

处于壮年时期 → prime