We use the present perfect tense to talk about things where there is a connection between the past and the present.
He has worked with three different companies.
He started working sometime in the past. Up to now he has worked for three companies.
As well as the present perfect simple, we can use the present perfect continuous tense to talk about events with a connection to the present.
Look at these 2 sentences:
I’ve been working on my thesis all month.
The main point is the action – working – and the action is unfinished.
I’ve written the conclusion to my thesis.
The main point is the finished result. The activity is finished but we can see the result now.
We use the present perfect continuous when the focus is on an activity that is unfinished.
Look at these two sentences.
I’ve read the book you lent me. It’s a gripping story.
I’ve been reading that book you lent me. I can’t wait to find out how it ends.
The present perfect simple (I’ve read) gives the idea of something completed while the present perfect continuous (I’ve been reading) suggests that something is not yet completed.
Look at these two sentences.
She’s been chatting to her friends online all day.
She’s chatted to fifty different people online.
The present perfect continuous (has been chatting) talks about how long something has been happening. The present perfect simple (has chatted) talks about how many people she chatted to up to the point when the person is speaking.
Look at these two sentences.
I’ve worked here for ten years.
I normally work in Canada but I’ve been working in Malta for six months now.
We can use the present perfect simple to talk about how long when we talk about something that’s permanent. But the present perfect continuous is often used to show that something is temporary.
So with actions that started in the past and continue to the present and are; temporary actions, actions where the focus is on duration – ‘how long’ or unfinished actions we usually use the present perfect continuous.