Present perfect continuous

The present perfect continuous is used to refer to an unspecified time between 'before now' and 'now'. The speaker is thinking about something that started but perhaps did not finish in that period of time. He/she is interested in the process as well as the result, and this process may still be going on, or may have just finished.

Actions that started in the past and continue in the present

She has been waiting for you all day (= and she's still waiting now).
I've been working on this report since eight o'clock this morning (= and I still haven't finished it).
They have been travelling since last October (= and they're not home yet).

Actions that have just finished, but we are interested in the results

She has been cooking since last night (= and the food on the table looks delicious).
It's been raining (= and the streets are still wet).
Someone's been eating my chips (= half of them have gone).

Forming the present perfect continuous

The present perfect continuous is made up of two elements: the present perfect of the verb 'to be' (have/has been), and the present participle of the main verb (base+ing)

Subject +has/have been +base+ing
She has been swimming

Affirmative: She has been / She's been running.
Negative: She hasn't been running.
Interrogative : Has she been running?
Interrogative negative: Hasn't she been running?

Example: present perfect continuous, TO LIVE
Affirmative Negative Interrogative
I have been living I haven't been living Have I been living?
You have been living You haven't been living Have you been living?
He, she, it has been living He hasn't been living Has she been living?
We have been living We haven't been living Have we been living?
You have been living You haven't been living Have you been living?
They have been living They haven't been living Have they been living?

Verbs without continuous forms

With verbs not normally used in the continuous form, use the simple present perfect instead (verbs such as: know, hate, hear, understand, want).
I've wanted to visit China for years.
She's known Robert since she was a child.
I've hated that music since I first heard it.
I've heard a lot about you recently.
We've understood everything.