IV. USING THE PERFECT CONTINUOUS TENSE FOR TIME
1. Comparison with the Regular Perfect Tense
1.1 Similarities
Both the Perfect and Perfect Continuous Tenses are used to talk about how long something happens. Or it can tell when a current action began. The Perfect Tense connects the starting time of an action to a later time of the action.
1.2 Differences
With the ordinary Perfect Tense, the time of the action stops at the time of speaking, or we are speaking only of the time when the action started until the time of speaking.
Examples
I have eaten my vegetables.
I have arrived at the airport.
1.3 Expect Action to Continue
With the Perfect Continuous Tense, there is the expectation that the action will continue past the current time of the action. Just like the ordinary continuous tense, the action can happen around a point in time. In this case, however, although there is usually an expectation that the action will continue, it might not continue.
Examples
I had been living in Baja, Mexico, for three years when I moved into my new apartment (but I continued to live in Baja).
I have been studying for three hours (but I am not finished yet).
By next year, I will have been working at the factory for five years. I plan to continue working there.
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