Questions 1 to 3 are based on the passage you have just heard。A.A.The importance of sleep
Questions 1 to 3 are based on the passage you have just heard。
A.A.The importance of sleep to a healthy life。
B.B.Reasons for Americans’ decline in sleep。
C.C.Some tips to improve the quality of sleep。
D.D.Diseases associated with lack of sleep。