meanwhile

"He felt lonely at the party; meanwhile, everyone else seemed to be having a wonderful time"

"The sun was setting behind the mountains; meanwhile, the city lights began to twinkle in the valley below"

"Can you finish the report, and meanwhile, I'll prepare the presentation slides?"

"She was studying for her exam; meanwhile, her brother was playing video games in the next room"

"Mom cooked dinner; meanwhile, I set the table"