Past Perfect Continuous vs Past Continuous: "had been doing" vs "was doing" (C1)

When the manager walked in, the team ___ the new design on the whiteboard.

By the time the manager walked in, the team ___ the design for hours and had finally agreed on a layout.

I ___ a cake when the doorbell rang, so it ended up burning.

Her hands trembled as she set down the screwdriver — she ___ heavy tools all afternoon and her arms ached.

When the lights suddenly went out, Tom ___ the news on his phone.

Anna ___ for hours when she finally received the email confirming her acceptance.

I noticed that my colleague ___ since the meeting ended — there were dark stains all down his shirt.

When the train pulled into the station, several passengers ___ for their suitcases on the overhead rack.

Tom looked exhausted at dinner; he ___ since six o'clock that morning.

She picked up the phone just as it ___ for the third time.

By the time the prize was finally announced, the audience ___ for over an hour.

When I caught a glimpse of her in the café, she ___ a serious-looking book and barely noticed me.

The chef was furious when he finally tasted it — the apprentice ___ the same simple sauce wrong for nearly a week.

She had been swimming for an hour when she realised the lifeguard ___ her since she'd first entered the water.

By the time I joined the table, the rest of the family ___ politics for half an hour and tempers were running high.