题目内容：
What is implied in the second paragraph?
A．Young children's biological clock has the same rhythm with that of the teenagers. B．People after puberty begin to go to bed earlier due to the change of the biological clock.
C．Children before puberty tend to fall asleep earlier at night than adolescents.
D．Teenagers go to bed later than they used to due to the light from the computer screen.
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答案解析：