There are 9 parts of speech or word classes in English language:
– nouns
– pronouns
– determiners
– verbs
– prepositions
– adjectives
– adverbs
– conjunctions
– interjections

Tense is a variation in the form of English verbs based on:
– the subject of the sentence
– time
– context of actions/events

Examples (variations based on time):
– I eat fried rice every day.
– I ate fried rice this morning.
– I will eat fried rice tomorrow.
– I am eating fried rice now.
– I have just eaten fried rice.
– I have been eating fried rice this whole week.

Examples (variations based on subject):
– I eat fried rice every day.
– He eats fried rice every day.
– She eats fried rice every day.
– My cat eats fried rice every day.
– You eat fried rice every day.
– We eat fried rice every day.
– They eat fried rice every day.

1. An action that was still happening when another action happened in the past.
– When I arrived last night, Ali had been waiting for two hours.
– I had been working at the company for five years when I got the promotion last year.

There are 5 verb forms:
– base form
– past simple form
– past participle form
– -ing form (present participle form)
– -s form

In Past Perfect Continuous Tense, we use these forms:
– -ing forms

We DO NOT not use these forms in Past Perfect Continuous:
– base forms
– -s forms
– past simple
– past participle

Positive Sentences

I + had been + -ing form
-> I’d been eating.
You + had been + -ing form
-> You’d been eating
We + had been + -ing form
-> We’d been eating
They + had been + -ing form
-> They’d been eating.

He + had been + -ing form
-> He’d been eating
She + had been + -ing form
-> She’d been eating
It + had been + -ing form
-> My cat had been eating

Negative Sentences

I + had not been + -ing form
-> I hadn’t been eating
You + had not been + -ing form
-> You hadn’t been eating
We + had not been + -ing form
-> We hadn’t been eating
They + had not been + -ing form
-> They hadn’t been eating

He + had not been + -ing form
-> He hadn’t been eating
She + had not been + -ing form
-> She hadn’t been eating
It + had not been + -ing form
-> My cat hadn’t been eating

Yes/No Questions

Had + I + been + -ing form
-> Had I been eating?
Yes, you had. / No, you hadn’t
Had + You + been + -ing form
-> Had you been eating?
Yes, I had. / No, I hadn’t
Had + We + been + -ing form
-> Had we been eating?
Yes, we had. / No, we hadn’t
Had + They + been + -ing form
-> Had they been eating?
Yes, they had. / No, they hadn’t

Had + He + been + -ing form
-> Had he been eating?
Yes, he had. / No, he hadn’t
Had + She + been + -ing form
-> Had she been eating?
Yes, she had. / No, she hadn’t
Had + It + been + -ing form
-> Had my cat been eating?
Yes, it had. / No, it hadn’t

Questions with Question Words (QW)

QW + Had + I + been + -ing form
-> What had I been doing?
QW + Had + You + been + -ing form
-> What had you been eating?
QW +Had + We + been + -ing form
-> What had we been doing?
QW +Had + They + been + -ing form
-> What had they been doing?

QW + Had + He + been + -ing form
-> What had he been doing?
QW + Had + She + been +-ing form
-> What had she been doing?
QW + Had + It + been + -ing form
-> What had your cat been eating?