1. They offered me a cup of tea.
A cup of tea was offered to me.
I was offered a cup of tea.
2. Students take examinations at the end of each term.
Examinations are taken at the end of each term ( by students).
3. The waiter will serve you breakfast in five minutes.
Your breakfast will be served in five minutes (by the waiter).
4. We have just sent for the doctor.
The doctor has just been sent for.
5. The lights went out when they were serving the meal.
The lights went out when the meal was being served.
6. The police were following him until he got to the office.
He was being followed by the police until he got to the office
7. They haven’t brought back my skates.
My skates haven’t been brought back (by them).
8. They are repairing the clock now.
The clock is being repaired by them now.
9. He had interrupted me.
I had been interrupted by him.
10. I will have read this book by 10 o’clock tomorrow.
This book will have been read by me by 10 o’clock tomorrow.