Преобразуйте в Indirect questions.
1. Is the post office open?
Do you know ________?
2. What time does the match start?
Do you know  ________?
3. Why has Leo gone home?
Do you know  ________?
4. Where did i put my mobile phone?
Do you know  ________?

и здесь просто раскройте Pr.Simple, Past Simple, Present Perfect
Years ago shells __(use) as money by a lot of north americans
Since 1999, the euro __(introduce) in most eur. countries
Every year, a lot of old coins __ (buy and sell) on the internet