听力原文：M: How come David is always so full of energy？W: He has a strange but highly effe

听力原文：M: How come David is always so full of energy？

W: He has a strange but highly effective way of sleeping.

M: What is that？

W: He takes a short sleep for an hour every six hours and has a total of four hours of sleep each day.

M: Where did he get that strange idea？

W: He read flora a book which said it was the best way for human beings, and he believed it.

M: How many hours do you sleep a day？

W: I need at least seven hours. I once tried to follow David's example, but it never worked out for me.

M: If I sleep during the day, I can never wake up.

W: Not everyone is a David I guess.

How does the man feel about David's way of sleeping？

A．It's effective.

B．It's strange.

C．It's the best.