Example → The thief had escaped when the police arrived.

Example → We'd finished all the water before we were halfway up the mountain.

Example → Sadly, the author died before she had finished writing her last book.

Whenever you want to talk about two actions that happened at different times in the past.

👉 we use the simple past to talk about events, states or habits at definite times in the past.

The answer is: Use the simple past!

- already → I called his office but he'd already left. - still → We still hadn’t finished cleaning when the guests arrived. - just → I went to visit her when she'd just moved to Berlin. - ever → Had you ever visited London before moving there? - never → No, I had never visited London before moving there.