He had been swimming in the swimming pool

Hi,

Are the following correct?

A) He had been swimming in the swimming pool for an hour.
B) I had been teaching English since 2015.
C) A stranger had been knocking at the door for 10 minutes.

Right. As Piscean says, B would only make sense in the present perfect: "I HAVE been teaching since 2015." After all, it's only 2016!

The others are fine if you're not swimming anymore and the stranger isn't knocking anymore.

We would usually say:

- He had been swimming in the pool for an hour.
- He had been in the swimming pool for an hour.
- He had been swimming for an hour.
- He had been in the pool for an hour.

But probably not:

- He had been swimming in the swimming pool for an hour.