Ответ:
Задание 1.
1.has been working
2.have been waiting
3.has been studying
Задание 2.
(--)
My granddad hasn't been picking fruits for 2 hours.
(Общий вопрос)
Has your granddad been picking fruits for 2 hours?
Yes, he has.
(Вопрос к подлежащему)
Who has been picking fruits for 2 hours?
My granddad has been picking fruits for 2 hours.
(Специальный вопрос)
What has your granddad been picking for 2 hours?
My granddad has been picking fruits for 2 hours.
How long has your granddad been picking fruits?
My granddad has been picking fruits for 2 hours.
(Разделительный)
Your granddad has been picking fruits for 2 hours, hasn't he?
No, he hasn't.