15. D I'm sorry I can't
16. B Great! Let's do that
III
1. B a -> an
2. used to picking -> used to be picked
3. A enough old -> old enough
4. B repaire -> repaired ( have + ST + Vpp )
IV
1. was sleeping
2. haven't painted
3. speaking
4. to be
V
1. informative
2. carefully
3. inconvenience
4. cyclists