The passive - Thể bị động

 
• passive voice

The Passive is formed with the appropriate tense of the verb to be + past participle

		Active voice		Passive Voice
Present Simple Past Simple Present Perfect Past perfect Present Continuous Past Continuous Future Simple Infinitive Modal + be + past part		He delivers letters. He delivered the letters. He has delivered the letters. He had delivered the letters. He is delivering the letters. He was delivering the letters. He will deliver the letters. He has to deliver the letters. He must deliver the letters.		Letters are delivered. The letters were delivered. The letters have been delivered. The letters had been delivered. The letters are being delivered. The letters were being delivered. The letters will be delivered. The letters have to be delivered. The letters must be delivered.

The Passive is used:

1. When the agent (= the person who does the action) is unknown, unimportant or obvious from the context.

My car was stolen. (We don't know who stole it.)

This church was built in 1815. (unimportant agent)

He has been arrested. (obviously by the police)

2. To make more polite or formal statements.

The car hasn't been cleaned. (more polite)

(You haven't cleaned the car. - less polite)

3. When the action is more important than the agent, as in processes, instructions, events, reports, headlines, news items, and advertisements.

30 people were killed in the earthquake

4. To put emphasis on the agent.

The new library will be opened by the Queen.

Changing from Active into Passive

• The object of the active verb becomes the subject in the new sentence.
• The active verb changes into a passive form and the subject of the active verb becomes the agent. The agent is introduced with by or it is omitted.

	Subject	Verb	Object	(agent)
Active	Picasso	painted	that picture.
Passive	That picture	was painted		by Picasso.

• After modal verbs (will, can, must, have to, should, may, ought to) we use be + past participle.

You can use the machine for cutting bread. The machine can be used for cutting bread.

• We use by + agent to say who or what carries out the action. We use with + instrument / material / ingredient to say what the agent used.

A cake was made by Tina. It was made with eggs, flour and sugar.

• We put the agent (= the person who does the action) into the passive sentence only if it adds information. When the agent is unknown, unimportant or obvious it is omitted. Agents such as people (in general), they, somebody, etc. are omitted.

Alexander Graham Bell invented the telephone.

The telephone was invented by Alexander Graham Bell. (The agent is not omitted because it adds information.)

Somebody pushed him. He was pushed (by somebody). (Unknown agent is omitted.)

The police arrested him. He was arrested (by the police). (Obvious agent is omitted.)