Column 1
It's terrible. Mary ... (have) an accident.
It's terrible. Mary has had an accident.
Large blocks of flats ... (appear) in the suburbs.
Large blocks of flats have appeared in the suburbs.
He ... (ride) his new bike all day.
He has been riding his new bike all day.
You ... (play) computer games since 4 o'clock.
You've been playing computer games since 4 o'clock.
She ... (work) since 7 o'clock.
She has been working since 7 o'clock.
How long ... you ... (be) her friend?
How long have you been her firend?
You are so dirty! What ... you ... (do)?
You are so dirty! What have you been doing?
How long ... you ... (study) English?
How long have you been studying English?
He ... just ... (eat) the last piece of cake.
He has just eaten the last piece of cake.
She ... (write) 2 excellent books.
She has written 2 excellent books.
She ... (travel) for 3 months.
She has been travelling for 3 months.
I ... (not see) him since last Xmas.
I haven't seen him since last Xmas.
My eyes hurt. I ... (work) on the computer all day.
My eyes hurt. I've been working on the computer all day.
How long ... they ... (wait) for you?
How long have they been waiting for you?
... Mike ... (fly) a kite before?
Has Mike flown a kite before?