Formula, Structure, and Rules of Future Perfect Continuous Tenses
Subject + will have been / will not have been + 1st form of verb+(ing) + object + Time reference.
- He will have been working in the factory for five years.
2. They will have been reading this book since 10 AM.
3. The kids will have enjoyed party.
4. The company will not have been advertising posts for one year.
5. He will not have been playing games since March.