1. He used to make so many mistakes

 2. Tom was a good employee and worked hard.

- Tom used to be a good employee and work hard.

3. My friend drove very carelessly when he was young.

-> My friend used to drive very carelessly when he was young.

4. That woman doesn't live alone any longer.

-> That woman used to live alone

5. He is no longer a famous actor.

-> He used to be a famous actor

 6. All the meetings were held in the auditorium.

-> All the meetings used to be held in the auditorium.

  7. My father managed a small business in this city but doesn't any more.

-> My-father used to manage a small business in this city but doesn't any more.

8. Ben drank a lot of coffee but now he prefers tea.

-> Ben used to drink a lot of coffee 

9. There was a hotel opposite the station, but it closed a long time ago.

-> There used to be a hotel opposite the station

10. The city had many old buildings ten years ago.

->There used to have many old buildings ten years ago.