The correct sentences:
1. A. If I find her address, I'll send her an invitation,
2.
B. If I go to the cinema, I will watch an interesting film.
3. A. He'll watch the film if he finishes early.
4. A. If they go to the disco, they will listen to loud music.
5.
B. If you wait a minute, I will ask my parents.
6. A. They will go to the party if they are invited.
7.
B. She will finish the work if you help her.
8.
B. If we don't see each other tomorrow, we will see each other next week,