5. a - gave, had missed.
b - had finished, went.
c - realized, had forgotten.
d - had been, knew.
e - thanked, had done.
6. a - Haven't seen
b - did you get
c - haven't finished
d - I read
e - Have you seen
f - i've done
7. a - have not read
b - lived
c - have you visited
d - have discovered
e - have never enjoyed