simple
Water ___ (boil) at 100°C.
boils
Please be quiet. I ___ (try) to concentrate.
am trying
I ___ (never/see) such a beautiful view before
have never seen
I ___ (wait) for you since 3 o’clock!
have been waiting
She usually ___ (take) the bus, but today she ___ (walk)
takes / is walking
My parents rarely ___ (agree) on anything
agree
She ___ (constantly/lose) her keys these days.
is constantly losing
She ___ (just/send) you an email.
has just sent
She ___ (work) too much lately; she really needs a break.
has been working
I ___ (not/see) him for ages — he ___ (travel) a lot lately.
haven’t seen / has been travellin
How often ___ you ___ (go) to the gym?
do you go
What project ___ you currently ___ (work on)?
are you currently working on
How many pages ___ you ___ (read) so far?
have you read
What ___ you ___ (do) while I was away?
have you been doing
Look! Someone ___ (break) the window!
has broken
Success usually ___ (depend) on hard work.
depends
The company ___ (expand) into new markets this year
is expanding
We ___ (not/decide) what to do about the problem yet.
haven’t decided
He’s tired because he ___ (train) for the marathon all week.
has been training
We ___ (try) to contact you all morning
have been trying
She ___ (not/believe) everything she reads online
doesn’t believe
Why ___ they ___ (argue) again? It’s the third time today
are they arguing
He ___ (win) several awards for his research
has won
It ___ (snow) all day — look at the streets
has been snowing
My English ___ (get) much better recently
has been getting