The affirmative past perfect continuous tense consists of:
The subject + had + been + infinitive + (-ing)
For example:
Last year from March to April, my family had been witnessing a financial crisis .
The negative past perfect continuous tense consists of:
The subject + had + not + been + infinitive + (-ing)
For example:
Last month from day 19th to day 21st , my teacher had been testing my English language.
The interrogative past perfect continuous tense:
How to make questions using the past perfect continuous tense:
Had + the subject + been + infinitive + (-ing) + the rest of the sentence?
For example:
The question: Had the children been playing for all night yesterday?
The answer: Yes, they had been playing. / No, they had not been playing.
Note: questions made with question words (how, when, where, why, etc,) are constructed as follows:
Question word + had + the subject (noun/ pronoun) + been + infinitive + (-ing) + the rest of the sentence?
For example:
The question: What had the children been playing for all night yesterday?
When to use the past perfect continuous tense?
Words that express the past perfect continuous tense:
The past perfect continuous tense is used to talk about actions that happened but lasted for a specific time in the past.
In this pattern, it always comes with the next expressions:
Yesterday (All night, all morning, etc.)
Last (week, month, year, etc.) from (time) to (time).
For example:
Last week from Tuesday to Friday, we had been studying.