填空题

Directions: This section is to test your ability to comprehend short passages. You will hear a recorded passage. After that you will hear five questions. Both the passage and the questions will be read two times. When you hear a question, you should complete the answer to it with a word or a short phrase (in no more than 3 words). The questions and incomplete answers are printed in your test paper. You should write your answers on the Answer Sheet correspondingly. Now listen to the passage.
At what time is the air the freshest in the day The air is never as fresh as early ______ .