I am going to write three sentences in the present perfect progressive, past perfect progressive, and future perfect progressive. Can you tell me what will happen after those specific times? DOes the possibility of him playing tennis after each specific time still exist for all three cases?

1. Sam has been playing tennis for three hours.

2. Sam had been playing tennis for three hours before his father called him in.

3. Sam will have been playing tennis for three hours by the time his father gets home.
1, 3: he may or not continue to play tennis after the reference time. You must provide more context in order to define that.

2: very probably not, as he was interrrupted by his father calling him in.
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Thank you, Marius.

I do agree that for No. 2, Sam probably stopped playing tennis when his father called him into the house possibly if he is to be a good young man as I think he is.Emotion: smile

If I changed the sentence like this, is it going to be like No.1 and 2 and the chances are that he might have continued or might not have continued?

Sam has been playing tennis for three hours before his father came home.

The possibility of him continuing and not continuing exist for all 3 cases and more context is needed to discern what might have happened next?
Yes, you have uncertainty also at 2 now.