Let's study Grammar " Passive voice "

The passive voice does exist for a reason, however, and its presence is not always to be despised. The passive is particularly useful (even recommended) in two situations:

• When it is more important to draw our attention to the person or thing acted upon: The unidentified victim was apparently struck during the early morning hours.
• When the actor in the situation is not important: The aurora borealis can be observed in the early morning hours.

The passive voice is especially helpful (and even regarded as mandatory) in scientific or technical writing or lab reports, where the actor is not really important but the process or principle being described is of ultimate importance. Instead of writing "I poured 20 cc of acid into the beaker," we would write "Twenty cc of acid is/was poured into the beaker." The passive voice is also useful when describing, say, a mechanical process in which the details of process are much more important than anyone's taking responsibility for the action: "The first coat of primer paint is applied immediately after the acid rinse."

We use the passive voice to good effect in a paragraph in which we wish to shift emphasis from what was the object in a first sentence to what becomes the subject in subsequent sentences.

The executive committee approved an entirely new policy for dealing with academic suspension and withdrawal. The policy had been written by a subcommittee on student behavior. If students withdraw from course work before suspension can take effect, the policy states, a mark of "IW" . . . .

The paragraph is clearly about this new policy so it is appropriate that policy move from being the object in the first sentence to being the subject of the second sentence. The passive voice allows for this transition.†

Passive Verb Formation

The passive forms of a verb are created by combining a form of the "to be verb" with the past participle of the main verb. Other helping verbs are also sometimes present: "The measure could have been killed in committee." The passive can be used, also, in various tenses. Let's take a look at the passive forms of "design."

Tense	Subject	Auxiliary		Past Participle
		Singular	Plural
Present	The car/cars	is	are	designed.
Present perfect	The car/cars	has been	have been	designed.
Past	The car/cars	was	were	designed.
Past perfect	The car/cars	had been	had been	designed.
Future	The car/cars	will be	will be	designed.
Future perfect	The car/cars	will have been	will have been	designed.
Present progressive	The car/cars	is being	are being	designed.
Past progressive	The car/cars	was being	were being	designed.

A sentence cast in the passive voice will not always include an agent of the action. For instance if a gorilla crushes a tin can, we could say "The tin can was crushed by the gorilla." But a perfectly good sentence would leave out the gorilla: "The tin can was crushed." Also, when an active sentence with an indirect object is recast in the passive, the indirect object can take on the role of subject in the passive sentence:

Active	Professor Villa gave Jorge an A.
Passive	An A was given to Jorge by Professor Villa.
Passive	Jorge was given an A.

Only transitive verbs (those that take objects) can be transformed into passive constructions. Furthermore, active sentences containing certain verbs cannot be transformed into passive structures. To have is the most important of these verbs. We can say "He has a new car," but we cannot say "A new car is had by him." We can say "Josefina lacked finesse," but we cannot say "Finesse was lacked." Here is a brief list of such verbs*:

resemble	look like	equal	agree with
mean	contain	hold	comprise
lack	suit	fit	become