Past Perfect Continuous

Form

Affirmative: (subject+had+been+verb+-ing)
Negative: (subject+had+not+been+verb+-ing)
Questions: (had+subject+been+verb+-ing)

Usage

The past perfect continuous certainly isn't the most frequently used (or taught) tense in the English language but it does have one major use:

To talk about longer actions or situations in the past that had been going on continuously up to the past moment that we are thinking about. We don't know or are not concerned with whether or not it continued after.

-Before eating lunch, she had been clipping her toenails for two hours.

Common students mistakes/errors:


As this tense has two auxiliary verbs- "had" and "been"- the omission of either one of those or the failure to add "-ing" to the main verb form are the major errors with this structure. Some problems with usage can also be expected as it can be easily confused with the past perfect (which stresses complete actions), and the past continuous.The latter implies that the actions happened around a time and not just up to that time.