Besides tenses, you must consider the voice of the sentence when using verbs. There are two kinds of voices in the English language: the active voice and the passive voice.
The Active Voice
In the active voice, the subject is the doer, or the agent, of
the verb. The following sentences are in the active voice.
When the subject is the agent (doer) of the verb, then the sentence is considered to be in the active voice.
The Passive Voice
In contrast, when the subject is NOT the agent of the verb, then the
sentence is considered to be in the passive voice. For example:
It is important to note that only transitive verbs, not intransitive, can be in the passive voice. Transitive verbs are those that are followed by an object, whereas intransitive verbs cannot be followed by an object. Read the following sentences:
The Form of the Passive
Tense
Form
Example
Simple Present
am/is/are + past participle
The class is taught by Mr. Johnson.
Present Progressive
am/is/are + being + past participle
The class is being taught by Mr. Johnson.
Present Perfect
has/have + been + past participle
The class has been taught by Mr. Johnson.
Simple Past
was/were + past participle
The class was taught by Mr. Johnson.
Past Progressive
was/were + being + past participle
The class was being taught by Mr. Johnson.
Past Perfect
had been + past participle
The class had been taught by Mr. Johnson.
Simple Future
will be + past participle
The class will be taught by Mr. Johnson.
OR
am/is/are going to be +past participle
The class is going to be taught by Mr. Johnson.
Future Perfect
will have been + past participle
The class will have been taught by Mr. Johnson.
The By-Phrase
When a sentence is in the passive voice, it may or may not identify the agent
of the verb. When it does specify the agent, the preposition by
is used. Read the following sentences:
Active or Passive?
If the passive has the same meaning as the active, then the question is, "When
should the passive be used?" It depends on the focus of the discourse.
In English, whatever is in the subject position usually receives focus, and
so the topic of the discourse, whether it is written or spoken, will be in the
subject position. For example, if you were asked to write about President
George W. Bush, you would want to focus on him - his character, his personality,
his policies, his activities - so you would want to write most of your sentences
with President Bush in the subject position and the verbs in the active voice.
On the other hand, if you were asked to write about his tax cut plan, you would
want to put the plan in the subject position since it is the focus of your writing,
but put the verbs in the passive voice because the plan really cannot 'do' anything.
It is done by someone else, whether it be President Bush or Congress, so you
might say something like "The tax cut plan was proposed by President Bush, and
after much deliberation, it was passed by Congress."