Question

He ............ 10 years of service by next March.

• A. will be completing
• B. will complete
• C. will have been completing
• D. shall complete

Answer 1

Answer:

C. will have been completing

This sentence refers to a future point in time ("by next March") and talks about an action that will have been in progress for a period of time (10 years) up to that point.

This is a classic example of the Future Perfect Continuous Tense, which is used to show:

An action that will have been continuing for some time up to a specific point in the future.

Structure of Future Perfect Continuous Tense:

Subject + will have been + present participle (-ing form)