Ребят, помогите! Вставьте в пропуски слова из списка:

1) Tom and I … friends since childhood.
a) has been
b) were
c) have been
d) was


2) We … a kitten 2 months ago.
a) bought
b) have bought
c) were buying
d) buy


3) He ... his work yet.
a) didn't finish
b) haven't finished
c) hasn't finished
d) hadn't finished