for ages.
They have been dancing for ages.
a book
She has been reading a book.
Why is she tired?
The baby has been crying for hours.
for a while
They have been talking for a while.
What has the dog been doing for the last half an hour?
It has been dancing.
15 minutes
She has been waiting for15 minutes.
for 20 minutes
He has been running for 20 minutes.
Mrs Strict ____ since forever.
Mrs Strict has been teaching since forever.
on-line / for 6 months.
They have been learning maths on-line for 6 months.
since she graduated
She has been taking photos since she graduated.
Why is he dirty?
He has been working in the garage for hours.
since they were 7
They have been sitting together since they were 7.
Why is she sleepy?
She has been playing with her toys.
What has the cat been doing for the last 10 minutes?
The cat has been hitting the bell for 10 minutes.
for 15 minutes.
They have been eating dinner for 15 minutes.
laugh/for the past 10 minutes
They have been laughing for the past 10 minutes.