Past Perfect Progressive

The Past Perfect Progressive Tense indicates a continuous action that was completed at some point in the past. This tense is formed with the modal "HAD" plus "BEEN," plus the present participle of the verb (with an -ing ending): "I had been working in the garden all morning.

Introducing the past perfect progressive tense

As its name suggests, the past perfect progressive combines features of both the perfect and the progressive tenses. The past perfect progressive is perfect because it refers to an action that was completed in the past. But it is also progressive because it refers to a continuous action that began and ended in the past. 

The past progressive perfect is formed by the conjunction of the helping verb phrase "had been" and the present participle form of the relevant verb. 

Using the temporal tense in a sentence

Here is an example of the past perfect progressive being used correctly in a sentence. 

"The man had been sleeping for four hours when he was suddenly awakened by an very loud crash of thunder."

In this sentence, the phrase "had been sleeping" is a correct use of the past perfect progressive. 

Now, here is an example of the past perfect progressive being used incorrectly within a sentence. 

"The two friends had been walked for several hours in the park, talking about anything and everything which came to their minds."

In this sentence, the past participle walked is being incorrectly used instead of the present participle walking. 

In case you are still a little confused, here are a couple basic rules you can follow when making use of the past perfect progressive. 

1. The past perfect progressive is always used to indicate a continuous action that has been completed in the past. That is, it refers to an action that began at some point in the past, and then ended at some other (later) point in the past. This is different from the simple past perfect, which refers to an instantaneous action that occurred at a single point in the past. 
2. The main challenge with the past perfect progressive may simply be to figure out if this is in fact the specific verb tense that you want to use to express the specific situation that you have in mind. Often, other tenses can express similar meanings; but the past perfect progressive calls specific attention to the fact that a past action occurred over time. 

The Past Perfect Progressive - An unusual verb tense

The past perfect progressive is a rather specialized verb tense that combines aspects of both the perfect and progressive tenses respectfully. In a way, the progressive aspect takes precedent over the perfect aspect, insofar the past perfect progressive makes use of the present participle and not the past participle of the relevant verb. The perfect part of the construction is signified through the unique helping verb combination that marks this tense: "had been". 

The past perfect progressive is (like all the other progressive tenses) primarily useful for conveying a sense of immediacy. Although the tense refers to a completed action, it also puts the reader alongside the person who was actually experiencing the action. The past perfect progressive "He had been sleeping" is more immediate than the simple past perfect construction "He had slept". Whereas the latter simply reports an event, the former calls more attention to the concrete experience of the person who had been engaged in the action. This can be highly useful, depending on the emphasis the writer would like to place on that experience.