The past perfect continuous

   He'd been waiting for twenty minutes when his train arrived.
 

The past perfect continuous is a tense for talking about activities that started sometime in the past and continued up to a specified point in the past.

 

affirmative:       subject + 'had' + 'been' + present participle

                           I'd been sending emails.

 

negative:           subject + 'had' + 'not' + 'been' + present participle

                            I hadn't been sending emails.

 

interrogative:    'had' + subject + 'been' + present participle

                            Had you been sending emails?

Usually, when we tell a story in the past, we use the past simple and past continuous but if we want to mention something which happened before the main narrative, we use the past perfect. For example, this is a story of something that happened two months ago, so all events before that are in the past perfect:

 

 "I met Sandra for lunch a couple of months ago.  I'd been wondering how she was."

"Where did you go?"

 

"To that new Italian place in the High Street. The food was amazing and it was good to catch up - I hadn't seen her for two years."

"And how was she?"

 

"Really happy. She'd been planning a trip to Japan. She'd decided which cities to visit and had just registered for a Japanese course."

"Had she booked her flights?"

 

"No she'd been comparing prices and hadn't decided which airline to go with."

 

It is used to talk about an action which started in the past and continued until a specified point in the past.
It can be useful in the following situations.  

Situation	Examples
When we talk about the duration of an activity	I'd been playing tennis since I was a child.   It had been snowing for two days.
In order to focus on activity rather than completion	I couldn't sleep because I'd been drinking a lot of coffee.
To explain something at a specified time in the past - it often answers the question, 'why?'	I was tired because I'd been working hard and I hadn't been sleeping well.   "Why were your clothes so dirty?" "I'd been playing football."
To talk about temporary situations	I'd been driving to work because of the train strike.   He'd been working at our head office in London to learn more about our operations there.

  

Note that we usually avoid using stative verbs in continuous forms and use the simple instead:

I'd often felt that he was dishonest.		I'd often been feeling...
I'd always wanted a Porsche.		I'd always been wanting...
He'd never believed me.		He'd never been believing...
Had you had a lot of different jobs?		Had you been having..?

1.         How long..? For/since

We use 'How long..?' to ask about duration.

     How long had they been learning English?

     How long had you been working in that department?

 

We can specify duration with either 'for' or 'since'. We use 'for' with a period of time and 'since' with a specific point in the past.

     They'd been learning English for two years.

     I'd been working in that department since February.

 

Some more examples:

For	Since
five minutes two hours days three weeks a long time	the day/week/month/year before the previous day/week/month/year October 1974 I was a child

 

Note that in negative sentences with 'for' or 'since', there are different possible meanings between the past perfect continuous and the past perfect simple. The past perfect continuous is less likely to be heard. For example:

I hadn't been to the theatre for ages - so I was really happy when Susan invited me to see Phantom of the Opera. [There was a long time between my last visit and Susan's invitation.]	I hadn't been going to the theatre for ages when I decided to start going again. [I used to go to the theatre regularly, then I didn't go for a long time and then I started going again. This structure is much less likely to be heard than the simple form.]
I hadn't spoken to Patty since Monday - she was on a business trip until Thursday. [We had no contact between Monday and Thursday.]	I hadn't been speaking to Patty since Monday but she apologised on Thursday and everything is OK now. [When we 'are not speaking to someone', it means we are deliberately not communicating because of an argument. So this means that between Monday and Thursday, we chose not to have any contact.]

 

 

2.         Just

 

We use 'just' in affirmative sentences and questions to suggest an activity that's very close in time to a specified point in the past:

     I'd just been reading your report when you arrived.

     Had you just been smoking? I could smell cigarettes.

3.         By

We often use the word 'by' when we want to specify a time at or before which something was done or achieved. For example:

     We drove from Scotland to Italy last summer. By the end of the first day, we'd been travelling for 14 hours and the children had been arguing all day so we decided to stop for a rest.

 

Note that these words and expressions can also be used with some other tenses.