PASSIVE VOICEA standard English sentence is written in the active voice, where the subject performs the action on the object:

John sold the house.

In a passive sentence, the object of the verb is moved to the beginning of the sentence:The house was sold by John.

The structure of a passive sentence is as follows:

(form of ) BE VERB + PAST PARTICIPLE

Past tense:The housewas soldby John.

Past continuous:The housewas being sold.

Past perfect:The househad been sold.

Present:The houseis sold

Present continuous:The houseis being sold

Present perfect:The househas been sold

Future:The housewill be soldThe houseis going to be sold

Modal verbs:The housecan be soldThe housemust be sold

Infinitives

The houseneeds to be sold.

Negative (past)The house was not sold.

Question form (past)Was the house sold?

Note that:

1. We use the past participle, no matter what the tense. For example:The project will be finished soon.

The sentence is set in the future. The ed on finished indicates passive voice.

2. Sometimes we use the word by with passive. However, sometimes by sounds unnatural.

3. Some sentences (with no object) cannot have a passive form:She jumped. (no passive form)

4. We have forms of the passive that use HAVE and GET instead of BE. Generally, this means you ordered someone to do a task for you:

I need to get my car repaired.(by someone)She had her nails painted.(by someone)

5. When should we use passive sentences?

Passive sentences are more formal. We use them in formal situations:Ladies and Gentlemen, the national anthem will now be played.

We use passive sentences when the object of the action is more important than the subject:This house was built in 1875. (not important who built it)

Compare these two sentences:1) Robert Singleton discovered the theory of quantum bias in 1875.2) The theory of quantum bias was discovered in 1875.

1) may be used in a text about Robert Singleton, whereas 2) in one about the theory of quantum bias