求翻译Onetheoryisthatwithdecreasedexposuretosunlight,thebiologicalclockthatregulatesmood,sleep,andhormonesisdelayed,runningmoreslowlyinwinter.Exposuretolightmayresetthebiologicalclock.Anothertheoryisthatbrainchemicalsthattransmitinformationbetweennerves,calledneurotransmitters(forexample,serotonin),maybealteredinindividualswithSAD.Itisbelievedthatexposuretolightcancorrecttheseimbalances.Chensayspeoplewhosufferfrom"theautumnblues"oftenareextremelyfatigued,lackenergy,needmoresleep,cravecarbohydrates,feelincreasedappetiteandgainweight."Itisasadseason,butyoucantrytomakeithappy.Remember,springalwayslivesinyourheart,"Chensays.