Section ADirections: This section is to test your ability to understand short dialogues. There are 5 recorded dialogues in it. After each dialogue, there is a recorded question. Both the dialogues and questions will be spoken only once. When you hear a question, you should decide on the correct answer from the 4 choices marked A) , B) , C) and D) given in your test paper. Then you should mark the corresponding letter on the Answer Sheet with a single line through the center.
A．Because he is so tired. B．Because he works late at night. C．Because he has eaten so much at night. D．Because he sleeps late at night.