A)
could
be able to
couldn't
not being able to
be able to
couldn't
be able to
couldn't
can
being able to
wouldn't be able to
b)
2) couldn't remember
3) be able to
4) can
5) been able to
6) couldn't
7) being able to
8) can't
9) being able to
10) be able to
11) be able to
12) can't