Past Perfect Continuous - Present Perfect Continuous - Future Perfect Continuous

I. Functions:

All Perfect Continuous tenses are used to emphasize that an action that happens continuously until a point in time. Their functions are a part of the normal Perfect tenses (Past Perfect, Present Perfect, Future Perfect).

Past Perfect Continuous is used to:

• Describe an action that started at some point and lasted until a point of time in the past.

Example: We had been waiting for 2 hours before you came. = We had waited for 2 hours before you came.

Present Perfect Continuous is used to:

• Describe an action that started at some point and lasts until the present.

Example: She has been reading the book for hours without stop. = She has read the book for hours without stop.

Future Perfect Continuous is used to:

• Describe an action that starts at some point and will until a point of time in the future.

Example: Mr.Carson will have been teaching for 25 years when he is 50. = Mr.Carson will have taught for 25 years when he is 50.

II. Form (Past Perfect Continuous):

+ Affirmative:

Subject + had been + V-ing

+ Negative:

Subject + had not been + V-ing

Shortened form: had not = hadn't

+ Question:

Had + Subject + been + V-ing

III. Form (Present Perfect Continuous):

+ Affirmative:

I/You/We/They + have been + V-ing

He/She/It + has been + V-ing

+ Negative:

I/You/We/They + have not been + V-ing

He/She/It + has not been + V-ing

Shortened form: have not = haven't; has not = hasn't

+ Question:

Have + I/you/we/they + been + V-ing

Has + he/she/it + been + V-ing

IV. Form (Future Perfect Continuous):

+ Affirmative:

Subject + will have been + V-ing

+ Negative:

Subject + will not have been + V-ing

Shortened form: will not have = won't have

+ Question:

Will + Subject + have been + V-ing