The present perfect tense is used to describe actions or events that started in the past and continue up to the present moment or actions or events that were completed very recently. It is formed using the auxiliary verb to have (in the present tense) followed by the past participle of the main verb.

I have finished my homework. (The speaker completed their homework at some point in the past, and the action is now finished.)
She has been living in New York for five years. (The speaker started living in New York at some point in the past, and the action is still ongoing up to the present moment.)

Here are some more examples of sentences in the present perfect tense:

They have visited three countries this year.

We have eaten at that restaurant twice.

He has finished his degree.

I have read that book before.

#1. The Present Perfect is formed by means of the Present Indefinite of the auxiliary verb to have and Participle II of the notional verb.

#2. In the interrogative form the auxiliary verb is placed before the subject. And in the negative form the negative particle not is placed after the auxiliary verb.

#3. The contracted affirmative forms are:

I’ve worked
He’s worked
You’ve worked

The contracted negative forms are:

I haven’t worked
He hasn’t worked
You haven’t worked

#4. The negative-interrogative forms are:

Has she not worked? = Hasn’t she worked?
Have you not worked? = Haven’t you worked?

The present perfect tense is often used to describe actions or events that started in the past and continue up to the present moment or actions or events that were completed very recently. It can also be used to describe experiences or accomplishments that have taken place at an unspecified time in the past.

#1. The Present Perfect denotes a completed action connected with the present.

Stop that car! They have killed a child. (Dreiser)

I am a little frightened for I have lost my way. (Dickens)

The Present Perfect is frequently used with the adverbs just, yet, already and of late.

Mr. Worthing, I suppose, has not returned from town yet! (Wilde)

I have just written to him. (Dickens)

He has done a great deal of work of late. (Locke)

#2. The Present Perfect is used in adverbial clauses of time after the conjunctions when, till, until, before, after, as soon as to denote an action completed before a definite moment in the future.

Don’t buy any more meat tomorrow until you have spoken to the mistress about it. (Bennett)

I am not going till you have answered me. (Galsworthy)

When the completion of the action is emphasized, the Present Perfect is used.

He will know the poem by heart when he has heard it twice.

#3. The Present Perfect denotes an action that began in the past, has been going on up to the present, and is still going on. In this case, either the starting point of the action is indicated or the whole period of duration. The preposition for is used to denote the whole period of duration. Since is used to indicate the starting point of the action. If the conjunction since introduces a clause, the verb in this clause is in the Past Indefinite.

Mr. Cowperwood, I have known you now for something like fourteen years. (Dreiser)

We have been engaged these four years. (Austen)

Where have you been since last Thursday? (Wilde)

Have you been alone, Florence, since I was here last? (Dickens)

The Present Perfect Inclusive is used:

• with verbs not admitting of the Continuous form.

“There is nothing to be done. She’s dead — has been dead for hours,” said the doctor. (Eliot)

• in negative sentences.

I have not slept since that night. (Bennett)

• with non-terminative verbs such as to live, to work, to study, to teach, to travel etc.

I have worked upon the problem for a long time without reaching any conclusion. (Shaw)

An action expressed, by the Past Indefinite belongs exclusively to the past, while the Present Perfect shows that a past occurrence is connected with the present time.

She is not well and has changed very much of late.

She changed very much a great many years ago. (Dickens)

The Present Perfect is never used with such adverbial modifiers of the past time as yesterday, the other day, last week etc. With such adverbial modifiers as today, this week etc. both the Present Perfect and the Past Indefinite are used. The tenses are used according to the principle mentioned above.

I have told you three times this week that she is coming home for a year. (Dreiser)

I want your sister, the woman who gave me money today. (Dickens)

With the adverb just the Present Perfect is used. Just now is less frequent than just.

I have just hired a new pianist from St. Joe — a Negro. (Dreiser)

With the expression just now the. Past Indefinite is used. I saw you come in just now. (Dreiser)

#1. In the following cases the Present Perfect is not used:

• What did you say?
• I did not hear your
• Where did you buy the book?
• Now I understand.
• I hear that Mary is in Cairo (to hear is not a verb of sense perception here, it means ‘the rumour reached me’).
• I am told that Mary is in
• I forget where he lives.
• I forget the title of the book (a certain fact). – BUT – I have forgotten to ring her up (a certain action).

#2. Verbs of sense perception and motion such as to hear, to see, to come, to arrive, to return in adverbial clauses of time are generally used in the Present Indefinite and not in the Present Perfect.

I am sure he will recognize the poem when he hears the first line.

We’ll ask Mr. Franklin, my dear, if you can wait till Mr. Franklin comes. (Collins)