Large blocks of flat ... (appear) in the suburbs.
Large blocks of flat have appeared in the suburbs.
He ... (ride) his new bike all day.
He has been riding his new bike all day.
... you ever ... (be) up a skyscraper?
Have you ever been up a skyscraper?
It's terrible. Mary ... (have) an accident.
It's terrible. Mary has had an accident.
How long ... you ... (be) her friend?
How long have you been her firend?
She ... (work) since 7 o'clock.
She has been working since 7 o'clock.
I ... (visit) it twice.
I've visited it twice.
You ... (play) computer games since 4 o'clock.
You've been playing computer games since 4 o'clock.
He ... just ... (eat) the last piece of cake.
He has just eaten the last piece of cake.
How long ... you ... (study) English?
How long have you been studying English?
How much ... the world population ... (increase) for the past decade?
How much has the world population increased for the past decade?
You are so dirty! What ... you ... (do)?
You are so dirty! What have you been doing?
I ... (not see) him since last Xmas.
I haven't seen him since last Xmas.
She ... (travel) for 3 months.
She has been travelling for 3 months.
I know it ... (reach) 7 billion in 2012.
I know it reached 7 billion in 2012.
She ... (write) 2 excellent books.
She has written 2 excellent books.
... Mike ... (fly) a kite before?
Has Mike flown a kite before?
How long ... they ... (wait) for you?
How long have they been waiting for you?
Where ... you ... (grow) up?
Where did you grow up?
My eyes hurt. I ... (work) on the computer all day.
My eyes hurt. I've been working on the computer all day.