I/1. Do you remember.....going
forgot
2. booking
had forgotten/ will telephone
II/
1. happily->happy
2. Did->Was
3. What->How
4. his->the
5. the newest->newer
III/
1. Be sure to get up early or you will late for school.
2. Remember to back at 10.30 or you won't have wine.
IV/
1. My sister wasn't able to swim last year.