Past Perfect Continuous

Past Perfect Continuous Tense
Form:               Past form of auxiliary HAVE + Past Participle BE + Present Participle ( had been sitting)
Negation:       We insert particle NOT after the first auxiliary verb ( had not been sitting)
Question:       Inversion of the subject and the first auxiliary verb ( Had I been sitting)
1) Longer action in the past before another action in the past
  * Tom had been waiting for two hours.
  * John was very tired. He had been running.
  * My car broke down. It hadn’t been running well for a long time.
  * Had the pilot been drinking before the crash?
  * I had been waiting for an hour by the time I received the reply.
2) Two actions happened in the past and we use PPC to clarify which action happened first
  * Mary looked tired. I could see that she had been studying for her English test recently.
  * The children were soaking wet. I knew they had been swimming in the lake.
  * Police had been tracking him for years and finally caught him.
  * Jones, who had been running, arrived out of breath.
  * I had been practicing for two days and was ready for the concert.
3) To make conclusions
  * There was a leak in the pipes, that’s why the water bill had been getting higher and higher each month.
  * The teacher looked very tired. She had been marking tests all day.
  * Her back was sore because she had been sitting at the computer all day.
  * Sam gained weight because he had been overeating.
  * Betty failed the final exam because she hadn’t been attending classes.
4) PPC can be interchangeable with the PPS without a change in meaning
  * I had slept/ had been sleeping all night.
  * I had lived/ had been living in Brazil before I moved to Serbia.
5) Answer the question ‘’how long’’
  * How long had you been waiting for the bus to come?
  * How many years had you been studying to be a teacher?
6) In third conditional to express imagined conditionals
  * If I had been...