3、Don’t you find that it is getting increasingly darker every day when you wake up for school? As winter comes, days become shorter while the nights become longer, in the past people slept more in winter, but in modern times we just use more electric light instead of sunlight to continue our normal routines.

But scientific research is finding that manhandling of electric light is making us sick.

Electric light is fooling the body’s biological clock into releasing awaking hormones ( 荷爾蒙)at the wrong times ,scientists say .This might be leading to seasonal fatigue (疲乏)and depression .

Much more than mental health is at stake, recent scientific studies have found that women, who work at night, have higher chances of getting breast-cancer.

“Electric lights are wonderful ,but as with a lot of other things ,we really mess ,things up ”said David Avery ,a psychiatrist (精神病專家).” Our ancestors evolved in a very regular light –dark cycle ,and our bodies just work better that way .”

Researchers have known for a long time that all living things have a biological clock that is linked to light ,Being of the natural day-night cycle can cause fatigue ,mood change and depression ,This is known as seasonal affective disorder ,or SAD.

Scientists disagree on the cause of SAD, Some say it is caused by winter’s late sunrises, others blame the early sunsets.

However, they all agree the perfect solution to SAD is to give up artificial light; it will quickly bring someone into a cycle of long, restful nights and easy awakenings at dawn.

But realistically most people need to use electric light in their everyday life. Ironically the next best solution is to use more bright lights to reset the body’s biological clock.

By getting bright light first thing in the morning it simulates (模擬)an earlier dawn and shifts the body clock forward ,according to Alfred Lewy ,a psychiatrist at Oregon Health & Science University .

A 2005 study done by the American Psychiatric Association showed that daily exposure to bright light was about as effective as medicine used to treat several forms of depression .

1． According to the text, electric light is bad for health mainly because __________

       A．is shortens people’s sleeping time

       B．it makes people upset and unable to concentrate

       C．it releases radiation and increases people’s chances of getting sick

       D．it stimulates the body to release awaking hormones at the wrong time

2． A person suffering from SAD may experience all of the following symptoms EXCEPT ___________

       A．weight loss        B．depression         C．fatigue                D．mood change

3．It can be inferred from the text that ___________

       A．women are more likely to suffer SAD than men

       B．SAD is a reaction to the lack of sunlight in winter

       C．scientists are still unclear about the cause of SAD

       D．a(chǎn)ll living things have a biological clock related to electric light

4．What is the best solution to treat people with SAD?

A．Using bright lights to reset the body’s clock

       B．Getting bright light in the morning to shift the body clock forward

       C．Daily exposure to bright light .

       D．Giving up artificial light

5．From the passage , we can find ________

A．people will sleep less and less as time goes on

B．hormones are important to your body

C．even though your biological clock is out of order ,you still feel OK

D．daily exposure to the bright light is as effective as medicine