1. I have finished my housework.
>> My housework has been finished.
2. He has signed the minute.
>> the minute has been signed by him.
3. He has taught at the school for 5 years.
->>the school has been taught at by him for 5 years.
4. We have collected the stamps for 9 weeks.
->>the stamps have been collected for 9 weeks by us.
5. They have taught Enlish for 20 years.
>>english has been taught by them for 20 years.