Past Perfect Progressive

Question

I came across a website that says using a past perfect continuous is a good way to show cause and effect. The writer then shows an example.

1. He was tired because he had been exercising so hard.

But later on he said using a past perfect continuous could cause an ambiguity. He gives an example—that was almost the same as the first sentence.

2. Jason was tired because he had been jogging.

He says the sentence could either mean Jason was still jogging at the moment, or that he had finished.

Here's my question: if using a past present continuous to show cause and effect could lead to ambiguity, why not use a past perfect instead if you want to show the action is completed? And past continuous to show the action is still ongoing?

• He was tired because he had exercised so hard.

• Jason was tired because he had jogged.

• He was tired because he was exercising so hard.

Answer 1

"Jason was tired because he had been jogging" can mean Jason was still jogging at the described moment in very limited circumstances.

"Jason was tired because he had been jogging for several hours already."

"Jason was tired because he had been jogging ever since the day he put on those accursed red shoes."

If there is a duration of time specified that continues up to 'now' (the point in time in the past tense rather than the past present continuous), then the past present continuous is correct.

"Here's my question, if using a Past Present Continuous to show cause and effect could lead to ambiguity, why not use Past Perfect?"

The two differ, albeit slightly. The difference between "Jason was tired because he had jogged" and "Jason was tired because he had been jogging" can be seen in the very syntax of the tenses. "To jog" is an action that one takes. "To be jogging" is a quality, a general state. In the former sentence Jason's 'current' state of fatigue derives from Jason's actions as an agent in the past, in the latter Jason's current state derives from Jason's aspects as a being.