PRESENT PERFECT

Structure

The present perfect is formed with the present simple of the auxiliary verb “have” and the past participle.

Positive Sentence:  

• I/you/we/they have (‘ve) gone
• He/she/it has (‘s) gone

Negative Sentence:

• I/you/we/they have not (haven’t) gone
• He/she/it has not (hasn’t) gone

Questions and short answers:

• Have they gone? Yes, they have.
• Has he gone? No, he hasn’t

Uses

In general we use the tense to talk about a present situation which is connected to the past.

A present situation that started in the past
“I’ve lived in the UK for 25 years”.

A series of actions that have happened in your life up to now
“I’ve been to Milan many times”

A result in the present of a past event
“I think I’ve prepared this report properly. I hope I don’t have to redo it”. (in this situation the current importance of the past event is important, not when it happened)

Time Expressions used with the present perfect

Ever and Never
We use ever and never to ask and talk about our general life experience.
“Have you ever visited the Maldives?”
“I have never used this software before.” (If the answer to the question is Yes we continue to give more information about specific events using the past simple.)

Already and YetWe use “already” in positive sentences and refers to something that has been done ahead of time
“He has already finished his homework” (he has finished it quicker than expected)

Yet is used in negative sentences and questions and suggests that something hasn’t happened or finished but will do.
“I haven’t finished the report yet“. (I am late but it will be finished)

“Have you seen that film yet?” 

“Haven’t you finished the houseworkyet?” (this negative question is often used when the person asking is annoyed or frustrated with the other person)

JustWe use “just” to describe something that happened a short time ago.
“He has just gone out to the shops. He won’t be long”.

For and sinceWe use the two expressions to refer to periods of time. Note the difference.” How long have you worked for Shell? 
“I have worked for Shell for 15 years” (length of time)
“I have worked for Shell since 1999.” (Start of the period)

Unfinished time
We use the present perfect for unfinished time and so we often use time expressions that include the present like the following:

this morning, today, this month, so far, up to now, recently, until now, recently, lately, over the last few years and so on

“I have been to the shops this morning“
“So far we have raised £2m for our charity”.
“I have been ver patient with them up to now“.
“I have had some good enquiries recently“.

PAST SIMPLE or PRESENT PERFECT?
Remember that the past simple describes actions in the past that are finished whilst the present perfect is used when the time period includes the present.

“I lived in Milan many years ago”
(completed. I live in London now)

“I’ve lived in Milan since 2008″
(a situation that started in the past and continues in the present: I still live in Milan)

PRESENT PERFECT CONTINUOUS

Structure

Present Perfect of “be” + the -ing form of the verb

Positive and Negative:
“I’ve been (I haven’t been) waiting here for more than an hour”
“She’s been (she hasn’t been) working here for many years”.

Questions:Have you been waiting long?
How long have you been working for your company?

Uses

An action or situation in progress from the past up to the present
“Production at this site has been increasing steadily in the last 5 years”

Emphasises the length of time of the action“I’ve been working on this post all morning”.

Repeated actions
” I’ve been calling her all morning but she’s not answering her phone”

The action may be finished or continuing, we only know from the context
“You’re late! I’ve been waiting for you for over an hour”. (the waiting is over)
“I’ve been waiting for over an hour,. Where is she?” (I’m still waiting)

The typical time expressions we use with this tense include:
all day, for months, for ages, recently, over the last few months/years, for and since.

PRESENT PERFECT or PRESENT PERFECT CONTINUOUS?
Sometimes there is no difference in meaning between these two tenses.

” I’ve worked/I’ve been working here for two years”.

The choice of tense often depends on where our focus is.

Focus on result = present perfect tense
” I’ve written the report. Here it is”. (result)

Focus on the action in progress and effort = present perfect continuous tense
“I’ve been writing this report all morning. I’m exhausted.” (note my effort)

If we give details on how much or how many we don’t use the continuos form.
“I’ve written four reports this week”.
“I’ve done a lot of consultancy work for the company in the last year”.