The use
Passive voice is used when the focus is on the action.
It is not important or not known, however, who or what is performing the action.
Example: My bike was stolen.
In the example above, the focus is on the fact that my bike was stolen.
I do not know, however, who did it.
Sometimes a statement in the passive voice is more polite than the active voice, as the following example shows:
Example: A mistake was made.
In this case, I focus on the fact that a mistake was made, but I do not blame anyone (e.g. You have made a mistake.).
The examples
Tense | Subject | Verbs | (prepositional) Object | |
Simple Present | Active: | Rita | writes | a letter |
Passive: | A letter | is written | by Rita | |
Simple Past | Active: | Rita | wrote | a letter |
Passive: | A letter | was written | by Rita | |
Present Perfect | Active: | Rita | has written | a letter |
Passive: | A letter | has been written | by Rita | |
Future | Active: | Rita | will write | a letter |
Passive: | A letter | will be written | by Rita | |
Auxiliary verbs | Active: | Rita | can write | a letter |
Passive: | A letter | can be written | by Rita |