Achickenlaysanegg.Youfeelsleepy.Andatreelosesitsleaves....
問題詳情：Achickenlaysanegg.Youfeelsleepy.Andatreelosesitsleaves.Allofthesethings,andmanymore,happeninacertainway,atacertaintimeeachdayoreachyear.Theytakeplacebecauseofsomethingcalledaninternalclock.The...