The Present simple tense

The Past perfect continuous tense.
(o’tgan tugallangan davomli zamon)

S + had been Ving

Had +S+ been Ving ?

S+had not been Ving

Signal words: for, since, how long, the whole day, all day …-kun bo’yi:
Biz bu zamonni asosan 2ta holatda ishlatamiz.
1.Bu zamonni o’tgan zamonda biror ish harakat bo’lganiga qadar malum vaqt mobaynida davom etgan ish harakatni ifodalash uchun ishlatamiz. Boshqacha qilib aytganda o’tgan zamonda biror ish harakat qancha vaqt mobaynida davom etganini ifodalash uchun ishlatamiz. Bunda for, since dan foydalanamiz.
Ken had been smoking for 30 years when he finally gave it up.
When he phoned me I had been working on the project since morning.
2.O’tgan zamonda sodir bo’lgan va natijasi o’tgan zamonda namoyon bo’lgan ish harakatlar haqida gapirganimizda ishlatamiz yani o’tgan zamonda sodir bo’lgan ish harakatni hozirgi zamoda turib hikoya qilinganda shu zamon ishlatiladi. Bunda odatda for, since ishlatilmaydi.
When the boys came into the house their clothes were dirty, their hair was untidy and one had a black eye. They had been fighting.
(bolalar uyga kirishganda ularning kiyimlari kir sochlari to’zg’igan va ulardan birini ko’zi ko’kargan edi. Ular urishishgan ekan.
He felt very tired when he came home as he had been playing football.
(u uyga kelganda qattiq charchaganini his qildi, chunki u futbol o’ynagan edi)
Past continiuos bilan  past perfect continuous ni signal so’zlari orqali farqlanadi.
When I came home my brother was sleeping. (p.continuous)
When I came home, my brother had been sleeping for 3 hours. (p.p. continuous)