In this section, you will hear several passages.
Listen to the passages carefully and then answer the questions that
follow. Questions 11 to 14 are based on the
following passage. At the end of the passage, you will be giv en 20 seconds to
answer the questions. Now, listen to the
passage. According to the research by NASA, an afternoon nap ______.
A．can greatly improve the efficiency of work B．can fall into a deep sleep and will wake up groggy C．makes people suffer a decline in their alertness D．is an admission of weakness