Bonjour,
Réponse :
1. If you like castles, you will find the most beautiful ones in Ireland.
2. If she visits us in July, we will show her the beautiful city of Cork.
3. I will buy you a ticket to Dublin if you pass the exam.
4. If they love Irish music, Tom will teach them how to play the harp.
On constate → If + présent simple // will + base verbale
Tu peux donc faire la dernière ( attention de ne pas oublier le "s" à la 3ème personne du présent simple )
5. If Anna ( to lend ) us her car, we ( to drive )to the Saint Patrick Day Celebration.