In previous sections, you learned about the perfect and progressive tenses. The perfect progressive tenses are used to indicate duration in the past. The three forms are:

PRESENT PERFECT PROGRESSIVE, PAST PERFECT PROGRESSIVE, and FUTURE PERFECT PROGRESSIVE

Here are examples of each:

PRESENT PERFECT PROGRESSIVE

I have been reading for one hour.

PAST PERFECT PROGRESSIVE

We had been traveling for three days when we ran out of money.

FUTURE PERFECT PROGRESSIVE

He will have been working there for a year by the time you arrive.

Examples of 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.