Formation of Passive sentences

a) Mr West              marks                 the English tests.
   (subject)                                           (object)   

The English tests              are marked          by  Mr West
     (subject)                                                        (performer)

B)Graham Greene wrote this book

This book was written by Graham Greene

C)Inspector Johnson has arrested five people
Five people have been arrested by Inspector Johnson

D)Computers solve many problems
Many problems are solved  by/with computers

E)The Queen is opening Parliament
Parliament is being opened by the Queen

F)The soldiers were building a new bridge
A new bridge was being built by the soldiers

G)Any secretary can type these letters
These letters can be typed by any secretary