题目内容：

Long nights of winter can leave even the most positive people feeling cranky(古怪的).But for about 5% of Americans, it’s more serious: seasonal affective disorder (SAD) is a type of depression that most occurs in the winter. Symptoms include loss of energy, eating more and difficulty in concentrating.

The cause of SAD is unknown, but darker days probably play a role. Reduced levels of natural sunlight can disrupt your body’s internal clock, which can lead to depression. It also causes a drop in serotonin (血清素)，a feel-good brain chemical. Severe cases may need antidepressant treatment. You can’t prevent the disorder from developing, but you can ease the symptoms.

Consider light therapy

Exposure to bright light that mimics(模仿)natural light is thought to affect mood-related brain chemicals and ease symptoms. It involves sitting in front of a special light box or wearing a cap-like lighted visor (盔甲)，for about 30 minutes a day. Another therapy uses a “dawn simulator” that is turned on early in the morning and gradually increases in brightness, allowing your body to wake up naturally. Light therapy can have minor side effects, such as eye strain and headaches, and it isn’t recommended for people with skin sensitivity.

Go outside

Yes, even if it’s cold and cloudy. Natural light is still good for you, and it can relieve your symptoms, especially if you head outdoors within two hours of waking up. At home, open the blinds and drapes to let in the light.

Eat right and exercise

Two health basics can help here, too. A well-balanced diet can improve energy levels, and regular physical activity works to boost your mood and ease stress and anxiety which can aggravate SAD symptoms.

Spend time with friends

Make an effort to see people you enjoy, even when you’re down. Staying connected to your social circle and participating in your regular activities can offer great support during the winter months.

1.Which of the following about SAD is NOT true?

A. It most occurs in the winter.

B. It may result in the absence of concentration.

C. It results from too much exposure to the sun.

D. Causes remain to be discovered.

2.Light therapy        .

A. is of no use unless being exposed to the sun for about 30 minutes a day

B. is a good way to anyone

C. can prevent seasonal affective disorder from developing

D. doesn’t suit those with skin sensitivity

3.What does the underlined word “aggravate” mean in the passage?

A. To make something worse.    B. To get rid of something.

C. To make anything better.    D. To get anything changed.

4.Which column could the passage come from?

A. Education.    B. Finance.

C. Travel.    D. Science.