PRESENT PERFET

Present Perfect (Present Perfect Tense)
The Present Perfect in English is a tense that is used to refer to actions that happen in the recent past and that have some connection with this. Its equivalent in Spanish is the Present Perfect:

I have sent the letter.
I have sent the letter.
(Indicates that the action just happened)

To build the affirmative form of Present Perfect should be used as auxiliary verb to have in the Simple Present and accompanied by the main verb in its past participle (either regular or irregular verbs verbs):

I have bought a new dress.
I have bought a new dress.
You have Studied the lesson. You have studied the lesson.
He has broken the window. He has broken the.
She has lost the keys. She has lost the keys.

Remember that the 3rd person singular should get the "S" on the side and it is the Simple Present.
Instead, to form a question we put the auxiliary at the beginning of the sentence, then the subject and then the main verb in past participle also:

Have I bought a new dress?
I bought a new dress?
Have you Studied the lesson? Have you studied the lesson?
You've broken the window? Broke the window?
She have lost the keys? Lost her keys?

Meanwhile, the negative is formed by placing the negation NOT between the auxiliary and the main verb, for example:

I have not bought a new dress. I have not bought a new dress.
You have not Studied the lesson. You have not studied the lesson.
I have not broken the window. He has not broken the.
She has not lost the keys. She has not lost the key.

You can also use the contracted form of denial or placing HAVE NOT HAS NOT accordingly.

Note that when we speak in Present Perfect should not mention the time when the action occurred, because to do so we should use the simple past, for example:

I have sold my car.
I have sold my car. (Present Perfect)

I sold my car this morning.
I sold my car this morning. (Past Simple)

present perfect is used in the English language to narrate events that have already occurred in a time-specific or not, in the past but still have a relevance in the present.

Corresponds in structure with the present perfect in Spanish, ie, the verb is constructed with the auxiliary verb have or if you have third-person singular (he, she, it), plus the participle of the verb: subject + verb + haveohas past participle, but not always in use: I have been married for two years. (I've been married two years.) .1

In the sense of the previous example, it is especially important to use to connect the past with the present, and even future. Hence, frequent use adverbs of time as for, since, etc.2