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?
 
swimmers-79592_640.png
Рис. \(1\). Swimming
 
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?
 
student-849825_640.png
Рис. \(2\). Working
 
Источники:
Рис. 1. Swimming, 2012, https://pixabay.com/images/id-79592/ Pixabay License CC0 Free for commercial use No attribution required
Рис. 2. Working, 2015, https://pixabay.com/images/id-849825/ Pixabay License CC0 Free for commercial use No attribution required