$\text{1.}$ She was tired because she had been running.

$\text{2.}$ They were hot because they had been dancing.

$\text{3.}$ The garden was flooded because it had been raining all night.

$\text{4.}$ Did they crash because they had been driving too fast?

$\text{5.}$ When I arrived, they had been waiting for over half an hour.

$\text{6.}$ When I got there, they hadn't been waiting long.

1. she had been running

2. they had been dancing

3. it had been raining all night

4. they had been waiting for over half an hour

5. they hadn't been waiting too long