1 . Running is often tiring and a lot of hard work, but nothing beats the feeling you get after finishing a long workout around the track.

But while it’s long been believed that endorphins (内啡肽) —chemicals in the body that cause happiness—are behind the so-called “runner’s high”, a study suggested that there may be more to this phenomenon than we previously knew.

According to a recent study published by a group of scientists from several German universities, a group of chemicals called endocannabinoids (内源性大麻素) may actually be responsible for this familiar great feeling.

To test this theory, the scientists turned to mice. Both mice and humans release high levels of endorphins and endocannabinoids after exercise. After exercising on running wheels, the mice seemed happy and relaxed and displayed no signs of anxiety. But after being given a drug to block their endorphins, the mice’s behavior didn’t seem to change. However, when their endocannabinoids were blocked with a different drug, their runners’ high symptoms seemed to fade.

“The long-held notion of endorphins being responsible for the runner’s high is false. Endorphins are effective pain relievers, but only when it comes to the pain in your body and muscles you feel after working out,” Patrick Lucas Austin wrote on science blog Lifchacker.

Similar studies are yet to be carried out on humans, but it’s already known that exercise is a highly effective way to get rid of stress or anxiety. The UK’s National Health Service even prescribes (开药 方) exercise to patients who are suffering from depression. “Being depressed can leave you feeling low in energy, which might put you off being more active. Regular exercise can improve your mood if you have depression, and its especially useful for people with mild to moderate (中等的) depression,” it wrote on its website.

It seems like nothing can beat that feeling we get after a good workout, even if we don’t fully understand where it comes from. At least if we’re feeling down, we know that all we have to do is to put on our running shoes.

1. What did scientists from German universities recently discover?

A．Working out is a highly effective way to treat depression.

B．The runner’s high could be caused by endocannabinoids.

C．Endorphins may contribute to one’s high spirits after running.

D．The level of endorphins and endocannabinoids could affect one’s mood.

2. Why did the scientists give mice drugs in their experiment?

A．To find what reduces the runner’s high symptoms.

B．To see the specific symptoms of the runner’s high.

C．To identify what is responsible for the runner’s high.

D．To test what influences the level of endocannabinoids released.

3. What does the underlined word “notion” mean?

A．Effect.

B．Goal.

C．Opinion.

D．Question

4. What can we know about regular workouts according to the UK’s National Health Service?

A．They can help ease depression symptoms.

B．They are the best way to treat depression.

C．They only work for those with serious depression.

D．They can help people completely recover from depression.

2 . One major reason Americans don’t get enough exercise is that they feel they don’t have enough time. It can be difficult to squeeze in the 75 minutes of aerobic (有氧的) exercise per week that federal guidelines recommend.    1    .

In a new analysis of 14 studies, researchers tracked deaths among more than 232,000 people from the U.S., Denmark, the U.K. and China over at least five years, and compared the findings with people’s self-reports about how much they ran. People who said they ran any amount were less likely to die than those who didn’t run at all.    2     This was true even for those who didn’t log a great deal of time. The analysis divided people into groups, with 50 minutes or less per week representing the group that ran the least―but still ran. ‘‘Regardless of how much you run, you can expect such benefits,” says Zeljko Pedisic, one of the authors of the new analysis published in the British Journal of Sports Medicine.

The analysis is the latest to illustrate the benefits of running on the human body. It’s what we evolved (进化) to do.     3     But as leisure-time exercise, running keeps us healthy. “One of the best ways to avoid having to see a doctor,” Zeljko says, “is to stay physically active.”

    4     Running is good at guarding against cancer partly because it uses up blood sugar, starving the cancer cells that rely on it for fuel. And it protects you in other ways not necessarily measured in the latest research: by decreasing inflammation (炎症), for example, which is at the root of many diseases, and stimulating the production of a protein that improves brain health.

    5     Neither were how often people ran and the pace they kept. As long as you’re running, more isn’t always better, especially given that the risk of injury increases with repetition.

A．People may no longer hunt wild animals for their next meal.

B．The physical demands of running affect our body in a beneficial way.

C．Some people run to prevent disease, and others run because it makes them feel better.

D．Runners were 27% less likely to die for any reason, compared with nonrunners.

E．But researchers point out, to infer something like that, they need the whole population measured.

F．But new research suggests people may be able to get life-lengthening benefits by running for far less time.

G．The good news is that running more than 50 minutes per week wasn’t linked to additional protections against dying.

3 . It’s 5:00 in the morning when the alarm(闹钟)rings in my ears. I roll out of bed and walk blindly through the dark into the bathroom. I turn on the light and put on my glasses. The house is still as I walk downstairs while my husband and three kids sleep peacefully. Usually I go for a long run, but today I choose my favorite exercise DVD, Insanity. Sweat pours down my face and into my eyes. My heart races as I force my body to finish each movement. As I near the end of the exercise, I feel extremely tired, but a smile is on my face. It’s not a smile because the DVD is over, but a smile of success from pushing my body to its extreme limit.

Some people enjoy shopping, smoking, food, work, or even chocolate. But I need exercise to get through each day. Some shake heads when they see me run through the town. Others get hurt when I refuse to try just one bite of their grandmother’s chocolate cake. They raise their eyebrows, surprised by my ＂no thank you＂, or by my choice to have a salad. Over the years, I have learned it’s okay to just say ＂no＂. I shouldn’t feel sorry for refusing food that I don’t want to eat.

So what drives me to roll out of bed at 5:00 a.m.? What gives me the reason to just say no to ice cream? Commitment. A commitment to change my life with a way that reduces daily anxiety, increases self-confidence and energy, extends life and above all improves my body shape. This is the point where a smile appears on my face as I look at myself in the mirror or try on my favorite pair of jeans that now fit just right. It’s through commitment and sweat that I can make a difference within myself inside and out.

1. Why is there a smile on the author’s face in the morning?

A．Because she sees her family sleeping peacefully.

B．Because she finishes her favorite exercise.

C．Because she enjoys the interesting DVD

D．Because she feels a sense of achievement.

2. Which of the following is true according to Paragraph 2?

A．She doesn’t treat others politely.

B．She likes to make others surprised.

C．Others don’t understand what she does.

D．Others try to help her by offering her food.

3. What does the underlined word ＂commitment＂ in the last paragraph mean?

A．Good health.	B．Firm belief.
C．A strong power.	D．A regular habit.

4. What can we learn about the author from the text?

A．She acts in a strange way.

B．She wants to look different from others.

C．She aims to develop a good body shape.

D．She has difficulty getting along with others.