a)We started working here three years ago.
We have worked here for three years. (have been working, если проходили Present Perfect Continious)
b)This is the first time I've been on a plane.
I haven't been on a plane before.
c)That's strange! My pen isn't here!
That's strange! My pen has disappeared!
d)Nicky and Jan aren't at this school any more.
Nicky and Jan don't go to this school.
e)I saw a friend of yours a few moments ago.
I just saw a friend of yours.
f)I'm still writing my letters.
I haven't finished writing my letters yet.
g)Is this your first visit to South America?
Have you ever been to South America before?
h)Oh no! My wallet is still in the car.
Oh no! I left my wallet in the car. (forgot)
i)It's a long time since we spoke to your sister.
We haven't spoken to your sister for a long time.
j)Is Anna still asleep?
Has Anna woken up yet?
Robert Palmer graduated from university in 1991. He studied Medicine but he has never worked as a doctor. When he finished his studies, he decided to become an artist. He thought that painting made him really happy! Robert has been painting for more than twelve years and so far he has sold more than twenty paintings. He has received quite a few awards and he has displayed his work in many art galleries around Europe. For the last two months Robert has been working on his latest painting which is called 'The Year 2053'.