The Perfect Tenses

Perfect tenses are formed with the helping verb to have and the past participle.

At 8 o’clock we say: “The news will come on the television at 8.30.”

At 8.30 we say: “The news is coming on the television.”

When the news broadcast is over we say: “The news has come on the television.” The action is finished, complete or perfect.

The Present Perfect Tense

I have just finished my lunch. (It implies that I am not hungry and cannot have anything more).

They have just reached home. (It implies that they are perhaps tired and need rest).

We use the present perfect tense for an action that took place in the past but we are more interested in the present consequences of the action than in its definite time in the past, e.g.

I have completed my work. (It implies that now I am free to play/watch television etc.).

We use the present perfect very often with indefinite adverbials of time. e.g. yet, already, often, never, always, sometimes, etc. We do not use a definite adverbial of time, e.g. ago, a minute ago, long ago, last night, yesterday, on Monday etc. With these we use the simple past.

We use the present perfect sometimes for an action which began in the past, continues in the present and may continue in the future, with adverbial phrase beginning with for and since, e.g.

I have been here for the past 15 years.

He has worked here since 1990.

I have not met him since Friday.

The past perfect tense is used for an action begun and completed before another action. It is used for the earlier of the two actions in the past. So we usually need it only in a sentence with two clauses and not in a simple sentence, e.g.

The bus had left before we reached the bus-stop.

As we had missed the bus we waited an hour for the next,

I had finished the work before the guests arrived.

He had left for his office when I got to his house.

It is used in indirect speech to replace both the simple past and the present perfect in direct speech, e.g.

She said, “I waited for you for an hour and then I went away.”

She said that she had waited for him for an hour and then she had gone away.

He said, “I have done this work.”

He said that he had done that work.

Notice that the present perfect is used in sentences which use after, before, when, until etc. in them.

It is used for an action beginning and ending at some given time in the future. So it is usually followed by a phrase like by this time or a clause like before something happens, e.g.

You will have reached Delhi by 9 o’clock tomorrow morning.

Mother will have prepared the lunch before we reach home.

The painters will have painted the building before the school re-opens.

My little sister will have gone to school by 8 o’clock.

Note that we use this tense when we are thinking of a point in the future time and looking back from it to what happened before.
Also note that if there is a second clause it is in the present tense, as is usual after conjunctions of time.