Choose the correct verb form. Sometimes both are possible

1. The team were exhausted because they (had worked/had been working/both) all night.
2. Miranda was tired because she
   [had waited|had been waiting|both] for several hours for the flight to board.
3. They were not starving during the flight because they
   [had had|had been having|both] a meal earlier in one of the airport restaurants.
4. After Ben
   [had picked up|had been picking up|both] his luggage, he took a taxi to his hotel.
5. My dad couldn't move his legs because he
   [had sat|had been sitting|both] down for so long.
6. Our flight arrived late because it
   [hadn't taken off|hadn't been taking off|both] on time.