Past Time Expressions  a long time ago  a little while ago  in the past  at one time  the day/ week before  yesterday  back then  in those days
 last night/ week/ month/ year/ time  on week/ month/ year ago
 when I was young/ younger/ 10  this morning
Time expressions usually go at the end or at the beginning of a sentence:
Yesterday, I went to school.
I went to school yesterday.
This week, I’m going to New York.
I’m going to New York this week.
“I was born in 1950. Back then, a lot of people didn’t have running water
in their houses. In those days, people had a toilet in the backyard. That
was a long time ago though, and now almost everyone in the UK has running water.”
“A little while ago, John’s tooth started hurting, so last week, he booked
an appointment to see the dentist. He went yesterday and it was a
surprisingly pleasant experience. At one time, the dentist was a place to
be feared, but not anymore.”