PRESENT PERFECT WITH FOR AND SINCE

 

How do we make the Present Perfect tense?

The structure of the Present Perfect is:

subject	+	auxiliary have	+	main verb
		conjugated in Present Simple
		have, has		past participle

The auxiliary verb (have) is conjugated in the Present Simple: have, has

The main verb is invariable in past participle form: -ed (or irregular)

For negative sentences we insert not between the auxiliary verb and the main verb.

For question sentences, we exchange the subject and the auxiliary verb ( El verbo auxiliar (have) se conjuga en el Presente Simple: have, hasEl verbo principal es invariable en forma de participio pasado: -ed (o irregular)Para oraciones negativas no insertamos entre el verbo auxiliar y el verbo principal.Para las oraciones de pregunta, intercambiamos el sujeto y el verbo auxiliar). 

Look at these example sentences with the Present Perfect tense:

	subject	auxiliary verb		main verb
+	I	have		seen	ET.
+	You	have		eaten	mine.
-	She	has	not	been	to Rome.
-	We	have	not	played	football.
?	Have	you		finished?
?	Have	they		done	it?

When we use the Present Perfect in speaking, we often contract the subject and auxiliary verb. We also sometimes do this in informal writing. (Cuando usamos el Presente Perfecto para hablar, a menudo contraemos el sujeto y el verbo auxiliar. A veces también hacemos esto por escrito informal). 

I have	I've
You have	You've
He has She has It has John has The car has	He's She's It's John's The car's
We have	We've
They have	They've

In negative sentences, we may contract the auxiliary verb and "not":

• You haven't won the contest.
• She hasn't heard from him.

He's or he's??? Be careful! The 's contraction is used for the auxiliary verbs have and be. For example, "It's eaten" can mean:

• It has eaten. (Present Perfect tense, active voice)
• It is eaten. (Present Simple tense, passive voice)

It is usually clear from the context.

Present Perfect for experience

We often use the Present Perfect to talk about experience from the past. We are not interested in when you did something. We only want to know if you did it:

I have seen an alien. He has lived in Bangkok. Have you been there? We have never eaten caviar.
past	present	future
!!!
The action or state was in the past.	In my head, I have a memory now.

For and Since with Present Perfect tense

We often use for and since with perfect tenses:

• We use for to talk about a period of time: five minutes, two weeks, six years
• We use since to talk about a point in past time: 9 o'clock, 1st January, Monday

for	since
a period of time	a point in past time
- - - - - - - - - - - -	- • - - - - - - - - - -
20 minutes	6.15pm
three days	Monday
6 months	January
4 years	1994
2 centuries	1800
a long time	I left school
ever	the beginning of time
etc	etc

Look at these example sentences using for and since with the Present Perfect tense:

• I have been here for twenty minutes.
• I have been here since 9 o'clock.
• John hasn't called for six months.
• John hasn't called since February.
• He has worked in New York for a long time.
• He has worked in New York since he left school.    PUEDEN REALIZAR EL SIGUIENTE TEST DE MANERA OPCIONAL A MODO DE PRACTICA:
• https://www.englishclub.com/grammar/verb-tenses_present-perfect_quiz.htm