PASSIVE VVOICE

Passive voice
a passive construction occurs when you make the object of an action in the subject of a sentence . that's whoever or whatever is performing the action is not the grammatical subject of the sentence . take a look at this passive repharasing of a familiar joke.

example passive voice :
tense : simple present
active : we take a cake
passive : a cake is taken by us

tense : simple past
active : we took a cake
passive : a cake was taken by us

tense : simple future
active : we will take a cake
passive : a cake will be taken by us

tense : present perfect
active : we has taken a cake
passive : a cake has been taken by us

when rewriting active sentence in the passive voice , note the following
* the object of the active sentence becomes the subject of the passive sentence
* the finite form of the verb is changed (to be + past participle)
* the object of the active sentence becomes the object of the passive sentence (or is dropped)

AGENT
in passive voice clause , we usually use a phrase beginning with by if we want to mention the agent - the person or thing that does the action , or that causes what happens . example

My sister makes sandwich every morning
* subject + Verb 1 + s/es + O + C

Sandwich is made by my sister every morning
* subject + tobe + V3 + agent + C