What tense is represented by the sentence "Will he have been writing for that many years?"

The tense represented by the sentence "Will he have been writing for that many years?" is the Future Perfect Continuous tense. This tense is used to express actions that will have been ongoing for a certain duration of time up to a specified point in the future.

In this case, the phrase "will have been writing" indicates an action (writing) that not only will occur in the future but will also span a period of time leading up to a future moment. The use of "for that many years" specifies the duration, emphasizing that the writing has been happening continuously and will continue for that amount of time before another future event occurs.

This tense is particularly useful for highlighting the length of an action or its completion in relation to another future moment, thereby providing a clearer context regarding future plans or expectations.