Объясните мне в языке время past perfect continuous! заранее !

Время Past Perfect Continuous указывает на действие, которое началось в продолжалось в течение некоторого времени и либо закончилось непосредственно перед неким моментом в или все еще не закончилось к некоему моменту в

I had been typing this text for 2 hours and then found it on the Internet.
Я набирал этот текст два часа, а потом нашел его в Интернете.

I had been waiting for his airplane for 2 hours when it was announced about delay.
Я ждал его самолет уже два часа, когда объявили об его задержке.
Образование Past Perfect Continuous

Утвердительные предложения:

I had been playing We had been playing
You had been playing You had been playing
He / she / it had been playing They had been playing
Вопросительные предложения:

Had I been playing? Had we been playing?
Had you been playing? Had you been playing?
Had he / she / been playing? Had they been playing?
Отрицательные предложения:

I had not been playing We had not been playing
You had not been playing You had not been playing
He / she / it had not been playing They had not been playing
Для того, чтобы поставить глагол в форму времени Past Perfect Continuous, требуется вс глагол to be во времени Past Perfect и причастие настоящего времени (форма V-ing) смыслового глагола.