Повествовательное предложение
They have been learning English for 2 years.-Они изучают английский 2 года
Отрицательное предложение
They haven’t been learning German for 2 years
Общий вопрос
Have they been learning English for 4 years
Альтернативные вопрос
Have they been learning English for 2 years or for 2 years?
Вопрос к подлежащему
Who has been learning English for 2 years?-they have
Специальный вопрос
How long have they been learning English?