Difference between the Past Perfect and Past Perfect Continuous
We use the Past Perfect to indicate that a completed action happened earlier than something else.
- By the time I was 15, my father had taught me how to drive a car.
- When you arrived, I had already finished my meal.
Now look at the below sentence:
- Jane had been browsing the Internet for about fifteen minutes when she suddenly noticed it was completely dark outside.
Why is Past Perfect Continuous used here?
We cannot use the Past Perfect in the above sentence because the action was not completed. (In other words, she did not stop browsing the Internet immediately after looking out of the window)
So, if we were to remove "for fifteen minutes", we would use the Past Continuous.
- Jane was browsing the Internet when she suddenly noticed it was completely dark outside.
Note: the Past Perfect Continuous often creates a kind of background for the rest of the sentence.
To sum it up in one sentence: the Past Perfect emphasizes completion (or the result of a completed action) while the Past Perfect Continuous emphasizes the duration or activity of an action.
One final example:
- By the time we arrived, he had left the house.
- By the time we arrived, he had been playing poker with his friends for 2 hours.