Read the following context and answer the question.
Context: After a long flight we sure love to get a good sleep . But it 's afternoon in Beijing and we need to adjust to the local time . We took a quick nap and woke up in the early evening in time to take a stroll around the neighborhood . Our hostel is nearby the old drum tower which is located near a busy street .
Question: Why does a long flight require the speaker to then have to adjust to the local time ?
Answer:


Once you 've entered a new region , your body must acclimate to the time difference