Теория:

Study some information about questions (general and special) in Future Perfect Continuous.
 
Для образования Future Perfect Continuous необходимо использовать структуру will have been и основной глагол с окончанием -ing.
Subject \(+\) will \(+\) have \(+\) been \(+\) Ving \(+\) other parts of the sentence.
Для построения вопросительных предложений нужно использовать следующий порядок слов.
 
General question
Will \(+\) subject \(+\) have \(+\) been \(+\) Ving \(+\) other parts of the sentence?
Will she have been swimming for an hour before I come?
 
swim.jpg
 
Special question
Question word (when, why, how, what...) \(+\) will \(+\) subject \(+\) have \(+\) been \(+\) Ving \(+\) other parts of the sentence?
Why will she have been working on the computer for two hours before I enter the room?
 
computer.jpg
Источники:
https://www.shutterstock.com/ru/video/search/young-businesswomen
https://www.jccdenver.org/fitness/swim-teams/