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)
Remember that the present perfect continuous has the meaning of "lately" or "recently." If you use the present perfect continuous in a question such as "Have you been feeling alright?", it can suggest that the person looks sick or unhealthy. A question such as "Have you been smoking?" can suggest that you smell the smoke on the person. Using this tense in a question suggests you can see, smell, hear or feel the results of the action. It is possible to insult someone by using this tense incorrectly.
REMEMBER Non-Continuous Verbs/ Mixed Verbs
It is important to remember that non-continuous verbs cannot be used in any continuous tenses. Also, certain non-continuous meanings for mixed verbs cannot be used in continuous tenses. Instead of using present perfect continuous with these verbs, you must use present perfect.
- Sam has been having his car for two years. Not Correct
- Sam has had his car for two years. Correct
The examples below show the placement for grammar adverbs such as: always, only, never, ever, still, just, etc.
- You have only been waiting here for one hour.
- Have you only been waiting here for one hour?
ACTIVE / PASSIVE
- Recently, John has been doing the work. Active
- Recently, the work has been being done by John. Passive
NOTE: Present perfect continuous is less commonly used in its passive form