Passive Overview

Structure

We form the passive using the relevant tense of the verb to be, plus the past participle of the main verb.

So for the verb clean, we would have:

Passive Summary of Tenses
Present Simple Present Continuous Past Simple Past Continuous Future Simple Going To Future Present Perfect Past Perfect Simple Can Should	The room is cleaned every day It is being cleaned now It was cleaned yesterday It was being cleaned at six yesterday It will be cleaned tomorrow It is going to be cleaned tomorrow It has been cleaned twice It had been cleaned before It can be cleaned easily It should be cleaned daily

To form the question, we put the auxiliary verb first:

Is it being cleaned today?
Had it been cleaned before?
Should it be cleaned daily?

Use

Look at this sentence:

They will deliver the letter tomorrow.

"the letter" is the object of the sentence. "they" is the subject. We can make "the letter" the subject:

The letter will be delivered tomorrow.

And if we want, we can include the subject of the first sentence:

The letter will be delivered by them tomorrow.

So we use the passive to say what happens to the subject of a sentence.

The bridge was painted in 1999.
Military jets are usually flown by men.
The flight to Boston will be delayed because of striking ground crew.

And we use an active sentence to say what a subject does:

John Exmoor painted that bridge in 1999.
Air Force pilots, usually men, fly military jets.
Striking ground crew will delay the departure of the Boston flight.

Sometimes, active sentences sound unnatural because who does the action is not important or not known. The action itself is important.

Tickets can be purchased from the booth at the entrance.
Spanish is spoken in much of South America.
Edward Moore was killed at his farm late last night.

The same sentences rewritten using the active would not be wrong, but the subject of these sentences would sound strange:

You can purchase tickets from the booth at the entrance.
People speak Spanish in much of South America.
Someone killed Edward Moore at his farm late last night.

Passive Present

Remember that the verb "to be" has to be used in all passive sentences and must be plural if the subject is plural:

This phone is made of plastic.
but
These chairs are made of wood.

After the verb "to be", you must use the past participle in all tenses.

Vintage wine is sold on the second floor.
not
Vintage wine is sell on the second floor.

The passive is used in the present often to describe processes:

The half-finished machine is then sent to Room 4 for painting.
The wine is then taken and put into bottles.

Passive Past

Remember with the passive that the past participle is always the same. You can see a list of common irregular verbs on this page.

It is the verb "to be" that changes:

I was driven around in the taxi at high speed.
We were treated terribly at the hotel last year.
I had to be taken to hospital immediately.

Note how the passive in English is more flexible than in other languages. Look at these two sentences:

The letter was sent by Express Post and arrived at 9am.
I was sent a letter by my wife.

In the first, it's clear that the subject of the passive sentence is the letter. In the second, it is not "I" that is sent, but, again, the letter. English allows for this type of construction. Other examples:

They were given a new TV for Christmas. (the TV is given, not 'they')
She was promised a pay rise by the boss. (the pay rise is promised, not 'she')