Practice choosing between Simple Past and Past Perfect

They --had leftleft by the time I --gothad gotten to the party.

She --cookedhad cooked dinner before they --arrivedhad arrived .

He --hadn't knowndidn't know that she --movedhad moved to a new city.

The play had already --started when we --had arrivedarrived at the theater.

By the time she --had finishedfinished her homework, her friends --wenthad gone home.

He had --met her before the event --had startedstarted .

She had --forgottenforgot his name by the time they --had metmet again.

When I --calledhad called her, she had already --gonewent to bed.

By the time the sun --had setset , they had --reached the campsite.