Past Perfect Continuous

The past perfect continuous tense, also known as the past perfect progressive, refers to an action that was ongoing in the past and that was completed before another past action or point in time. Realistically it's not a tense we use often.

Positive	Positive short form	Negative	Negative short form
I have been singing	I've been singing	I have not been singing	I haven't been singing
You have been arguing	You've been arguing	You have not been arguing	You haven't been arguing
She, he, it has been working	She, he, it's been working	She, he, it has not been working	She, he, it hasn't been working
We have been fighting	We've been fighting	We have not been fighting	We haven't been fighting
They have been laughing	They've been laughing	They have not been laughing	They haven't been laughing

Marcus had been working on the project all day before he realized he forgot his laptop at home.
The children had been playing outside in the rain and were very happy when they came inside.
Before the concert began, the musicians had been practicing hard for weeks.
I could smell cigarettes. My mom had been smoking.