a. Form: S + Will/ Shall + Have + Been + Ving
- To express an action that will be happening before another action in the future. Ex: when I get my diplomat, I will have been learning at this school for 3 years. Mike is leaving next month; he will have been working here 20 years.
- We use this form when we imagine looking back from the future; it also focuses on the action going on. Ex: I will have been writing the report for a week.