This tense is often used with the following time expressions:
...since + specific point in time
... for + amount of time
Subject + has / have + been + verb + ing + object(s) + time Expression
He's been cleaning house for two hours.
Subject + has / have not (hasn't / haven't) + been + verb + ing + object(s) + time Expression
Janice hasn't been studying for too long.
(Question Word) + has / have + subject + been + verb + ing + object(s) + (time Expression)
How long have you been working in the garden?
Take this present perfect continuous quiz to check your understanding.
If you are a teacher, use this guide on how to teach the present perfect continuous tense for more help.