Passive voice – Usage

The passive voice in English is used to:

– When we don’t know the agent:
My bag has been stolen. (You don’t know by whom)
– When the agent is obvious:
The thief was arrested. (The police arrest people)
– When the agent is not important:
Our website is being redesigned. (The action or the outcome are important)

If an agent needs to be added, use “by” (for people) and “with” (for instruments):

The report was written by Anna.
It’s best to mix the ingredients with a wooden spoon.

The passive voice is also more frequently used in formal contexts, for technical documentation, in scientific/academic texts, in legal texts. For example:

The premises can be occupied by no more than 10 inhabitants.
A new account has been arranged for your convenience.
In this experiment the acid is added to the mixture.