I smoked when I was young.
I smoked when I was young.
I used to be thin when I was young.
I stopped smoking.
I was unable to breathe because of smoke.
I was unable to breathe because of the smoke.
I was quick tempered when I was young.
I was young once.
I used to drink a great deal when I was young.
I had chicken pox when I was a kid.
I had chicken pox when I was a kid.
I was a wild young man at that time.