A.To urge children to get enough sleep.B.To relieve the burden of school children.C.To dissuade teenagers from staying up late.D.To tell Americans to have 9 hours of sleep every night.
A.To urge children to get enough sleep.
B.To relieve the burden of school children.
C.To dissuade teenagers from staying up late.
D.To tell Americans to have 9 hours of sleep every night.