Complete the sentences with the correct forms of the verbs in the brackets. Use the past perfect continuous.
1. Orla felt fit for the marathon because she (exercise) a lot.
2. You got sick because you (eat) all the time.
3. The passengers (wait) for four hours before the ground staff could finally give them information on the delay of their flight.
4. He (take) the dog for a walk for two hours yesterday.