Passive Form

Active verbs are used to say what the subject does. The Passive is used to say what happens to the subject. The passive is normally used to create an impersonal effect. It draws attention to the result of an action rather than to the agent performing it, who may not even be mentioned.

The verb in the passive sentence consists of the auxiliary verb be + past participle of the main verb.

PRESENT SIMPLE

active	We kindly ask* visitors not to take pictures.*
passive	Visitors are* kindly asked not to take pictures.*

PAST SIMPLE

active	We kindly asked* visitors not to take pictures.*
passive	Visitors were* kindly asked not to take pictures.*

PRESENT PERFECT

active	We have kindly asked* visitors not to take pictures.*
passive	Visitors have been* kindly asked not to take pictures.*

PAST PERFECT

active	We had* kindly asked visitors not to take pictures.*
passive	Visitors had been* kindly asked not to take pictures.*

PRESENT CONTINUOUS

active	They are painting* the museum.*
passive	The museum is being painted.

PAST CONTINUOUS

active	They were painting* the museum.*
passive	The museum was being painted.

If the agent performing the action is mentioned, it is introduced using the preposition by.