Question

How to form passive sentences?

Answer 1

Unlike the active voice, in which the emphasis is on the one who practiced the action, that is, on the subject, the passive voice is concerned with emphasizing the object, that is, the one who suffers the action expressed by the verb.
An example of an active voice would be:
The men built that house. The men built that house.
Already when moving to the passive voice, the first step is to invert the object, placing it at the beginning of the sentence.
That house was built by the men. That house was built by the men.
Note that, in addition to the object inversion, there was also a change in the verbal tense of the sentence. In the active voice, the verb was in the simple past, and in the passive voice was added the past of the verb "to be" plus the participle of the verb. In addition, there was also the addition of by shortly after the verbal phrase.
Not all phrases will follow the same template above. It is necessary, therefore, to be attentive to the verbal tense of the phrase in the active voice, to know in which verbal time it should come in the passive voice. Below is a table that illustrates the tenses of the active voice and the passive voice:
Active voice time Passive voiceExamples
Simple present
Are / is + participleActive voice: Bob writes letters. (Bob writes letters).
Passive Voice: Letters are written by Bob. (Letters are written by Bob).
Present continuous
Is / are + being + verb in the participleActive voice: Bob is writing a letter. (Bob is writing a letter).
Passive voice: A letter is being written by Bob. (A letter is being written by Bob).
Simple past
Was / were + participleBob wrote a letter. (Bob wrote a letter).
Passive voice: A letter was written by Bob. (A letter was written by Bob).
Past continuous
Was / were + being + verb in the participleActive voice: Bob was writing a letter. (Bob was writing a letter).
Passive voice: A letter was being written by Bob. (A letter was being written by Bob).
Simple future
Will be + verb in participleActive voice: Bob will write a letter. (Bob will write a letter).
Passive voice: A letter will be written by Bob. (A letter will be written by Bob).
Perfect gift
Has / have + been + verb in the participleActive Voice: Bob has written letters. (Bob has written letters).
Passive voice: Letters have been written by Bob. (Letters have been written by Bob).
Past Perfect
Had been + verb in participleActive Voice: Bob had written letters. (Bob had written letters).
Passive Voice: Letters had been written by Bob. (Letters had been written by Bob).
Future with "going to"
Am / is + are + going to be + verb in participleActive voice: Bob is going to write a letter. (Bob will write a letter).
Passive voice: A letter is going to be written by Bob. (A letter will be written by Bob).
Note: When the subject of the active voice is indeterminate (someone - someone, people - people), the agent of the passive (the one who underwent the action by the verb), nor by is not placed.
Ex.:
Active voice: Someone opened the gate. Someone opened the gate.Passive voice: The gate was opened. (The gate was opened).