Из активного в пасивный подалуйста)

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