PASSIVE VOICE

The passive voice is used when focusing on the person or thing affected by an action. The passive voice is less usual than the active voice. The active voice is the "normal" voice. But sometimes we need the passive voice. In this lesson we look at how to construct the passive voice, when to use it and how to conjugate it.

We use the passive when:

• We want to make the active object more important
• We do not know the active subject

The structure of the passive voice is :

Passive subject + Auxiliary verb (be) + Past participle + By + Agent

Note :

The main verb is always in its past participle form.

We always use by to introduce the passive object

When rewriting active sentences in passive voice, note the following :

• the object of the active sentence becomes the subject of the passive sentence
• the finite form of the verb is changed (to be + past participle)
• the subject of the active sentence becomes the object of the passive sentence (or is dropped)
• only verbs that take an object can be used in the passive voice.

Look at these sentences :

Active	Passive	Time Reference
They make Fords in Cologne.	Fords are made in Cologne.	Present Simple
Susan is cooking dinner.	Dinner is being cooked by Susan	Present Continuous
James Joyce wrote "Dubliners".	"Dubliners" was written by James Joyces.	Past Simple
They were painting the house when I arrived.	The house was being painted when I arrived.	Past Continuous
They have produced over 20 models in the past two years.	Over 20 models have been produced in the past two years.	Present Perfect
They are going to build a new factory in Portland.	A new factory is going to be built in Portland.	Future Intention with Going to
I will finish it tomorrow.	It will be finished tomorrow.	Future Simple

Learn more in these related links :
http://www.ego4u.com/en/cram-up/grammar/passive
http://www.englishclub.com/grammar/verbs-voice_passive.htm
http://www.unc.edu/depts/wcweb/handouts/passivevoice.html