1. PRESENT PERFECT PROGRESSIVE

This tense indicates duration of an activity beginning in the past and continuing into the present. It is often used with time words like for, since, all day, etc.

Begin with 'has' or 'have' + 'been' followed by -ing form of the verb.

–They have been watching television for three hours.

NOTE: When the present perfect progressive is used without reference to time, it indicates a general activity in progress recently:

–I have been thinking about renting a car.

2. PAST PERFECT PROGRESSIVE

This tense emphasizes the duration of an activity that was in progress before another activity or time in the past.

Begin with 'had' + 'been' followed by -ing form of the verb.

–I had been waiting for an hour when the doctor arrived.

3. FUTURE PERFECT PROGRESSIVE

This tense indicates the duration of an activity that will be in progress before another time or event in the future.

Begin with 'will have' + 'been' followed by -ing form of the verb.

–When he retires, he will have been working for 40 years.

Examples of Forming the Perfect Progressive Tenses

• I have been waiting on you for an hour.
• He will have been working here for fifty years when he retires.