Из активного в пасивный подалуйста)

The letters are delivered at 8.00 by postman
This hotel was built two  years ago by someone 
A lot of preservatives are used in food in these days by them
Has your question been answered by anyone
Your keys were found  on top of the photocopier by somebody
Reference books  should not be taken out of the library 
The rate of taxation has been increased to forty per cent by them
Pencillin was discovered in 1928 by scientist