Question

Were swimming - the past perfect continuous had become - the past perfect continuous

Answer 1

Had been swimming - the past perfect continuous

had been becoming - the past perfect continuous

Answer 2

The past perfect continuous is used to describe an action or event that started in the past and continued up until another point in the past.

For example:

• We had been swimming for two hours when the storm hit. (past perfect continuous)

This means that the swimming had started in the past and continued for two hours up until the storm hit.

Similarly, "had become" can also be used in the past perfect continuous to describe a state or condition that had started in the past and continued up until another point in the past.

For example:

• By the time we arrived, the situation had become increasingly difficult. (past perfect continuous)

This means that the situation had started in the past and continued to become increasingly difficult up until the time we arrived.