Something had been happening for a perioud of time before something else.
Our game of tennis was interrupted. We'd been playing for about half an hour when it started to rain very heavily.
I still can't agree with you.The exercise wants you to forward shift the past perfect continuous to the past continuous.
The writer of the exercise agrees with jutfrank.I still can't agree with you.
Which is what jutfrank did.The task is to convert it tothedirect speech.