Exercises to learn English

Passive voice: some uses

We often use the passive voice instead of the active voice when:

it is not necessary to mention the person who carried out the action:

Neighbour: The milk is delivered in the morning.

we do not know who carried out the action:

Sheila: Oh, my handbag has been stolen!

we are more interested in the action than in the person who carried out the action:

America was discovered in 1492.

When you want to mention who the action was performed by, you have to put the preposition by before the agent:

On September 11, 2001, the Twin Towers were destroyed by a group of terrorists who had hijacked two aeroplanes.