a) I've finished (not yet)
b) they've booked the restaurant (yet?)
c) We've ordered the champagne ( already)
d) Anna's been studying hard ( five hours)
e) Jim's been cleaning his bike ( how long?)
f) I've seen Jim (just)
g) We've been helping Mary ( five o'clock)
h) They haven't spoken to each other ( fours years)
i) Nobody has sent me a letter (a long time)
j) It hasn't rained here ( June)