...the BEST English-Learner's site on the 'Net!
Printable Page: HERE
|USAGE:||Past perfect progressive is used for an event that was in progress in the past.
It is also used for events that happened in the recent past.
|EXAMPLE:||The police had been looking for the robber for two months before they finally found him.|
|MEANING:||The police actively searched for two months, and THEN they found the robber.
"had been looking" tells us that the event took a while to finish.
|FORMAT:||had + been + ___ing = They had been looking for two months.|