PAST PERFECT CONTINUOUS TENSE

POSITIVES

I had been working there for five years when my first son was born
They had been playing football for half an hour when the rain started
We had been waiting for two hours before the manager called us
You had been reading my book for three days before you returned it to me

He had been learning Japanese for two years before they went to Japan last year
She had been washing since early in the morning before I came to her house yesterday
My dog had been sleeping for almost three hours when the cat suddenly jumped on it

NEGATIVES

I hadn't been studying for two hours when you came last night
They hadn't been waiting for a long time when you got here
He hadn't been running the business for years before they moved to Europe
She hadn't been reading the book for hours before I asked her to return it

INTERROGATIVES

Had you been working there for five years when your son was born?
Had she been trying to find you for a long time before she met you in the mall?

How long had you been lerning English when you got the job in the mining company?
What had you been doing there for years before your father visited you last year?