We can use the present perfect continuous to:
1. talk about an activity which started in the past and is still going on now:
He has been working here for three years. He started working in McCarthy's in 2003 and now (in 2006) he's still working there.
She' s been living in London since 2000.
2. talk about a past activity which has a result in the present:
Have you been decorating? Your clothes are covered in paint!
He 's been working all day so he is tired now.
The present perfect continuous has two parts - the main verb and the auxiliary verbs.
He has been thinking about it for ages.
She's been driving since 4 o'clock.
In these examples, the main verbs are 'to think and 'to drive'. In the present perfect continuous, we use the present participle form of the main verb (ing).
The auxiliary verbs are 'to have ' + ' to be'. When we make the present perfect continuous we use the present simple form of 'to have' + been:
I/you/we/they have been .
he/she/it has been .
The 'have' form is often shortened to: I 've , she 's , we 've , etc.
He 's been learning English for six months.
They' ve been looking for a house for months.
We use the auxiliaries to make negatives, questions and use only the 'have' auxiliary in short answers.
I haven't been living here long.
Has she been watching TV all morning?
Yes, she has.
No, she hasn't.
For and since are often used with the present perfect and present perfect continuous. We use for when we're talking about a period of time and since when we mention the start of a period of time.
...a long time
...they were children
...the last time
Stative (or state) verbs describe states (things that don't change easily or quickly, for example, what you believe, think or own) rather than actions (jump, talk or buy). These verbs are not normally used in the continuous form (ing). For example:
I've been interested in commerce ever since I was young.
She hasn't believed in Santa Clause for 20 years.
For information about the stative verbs, see language point Episode 4.
to jump at the chance:
to eagerly accept a challenge or chance to do something