Førnutid (perfektum) i PASSIV

Oversæt nedenstående aktive sætninger til passiv!
Eksempel:
They have painted the windows.
The windows have been painted.

They have given my sister some tickets to the concert.
My sister has         some tickets to the concert.

The management has offered them more money.
They             more money by the management.

He has boiled the potatoes for 20 minutes.
The potatoes             for 20 minutes.

They have planted some more trees in their front garden.
Some more trees             in their front garden.

They have found two more people alive after the accident.
Two more people             alive after the accident.

He has sold all his furniture.
All his furniture            .

Many people have read these novels.
These novels             by many people.