2 . 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.

3 . What sport does the woman like?

A．Skating.

B．Skiing.

C．Swimming.

4 . If you are already making the time to exercise, it is good indeed! With such busy lives, it can be hard to try and find the time to work out.     1     Working out in the morning provides additional benefits beyond being physically fit.

Your productivity is improved. Exercising makes you more awake and ready to handle whatever is ahead of you for the day.     2    

Your metabolism(新陈代谢) gets a head start.     3     If you work out in the mornings, then you will be getting the calorie(卡路里) burning benefits for the whole day, not in your sleep.

    4     Studies found that people who woke up early for exercise slept better than those who exercised in the evening. Exercise energizes you, so it is more difficult to relax and have a peaceful sleep when you are very excited.

    5     If you work out bright and early in the morning, you will be more likely to stick to healthy food choices throughout the day. Who would want to ruin their good workout by eating junk food? You will want to continue to focus on positive choices.

There are a lot of benefits to working out, especially in the mornings. Set your alarm clock an hour early and push yourself to work out! You will feel energized all day long.

A．You will stick to your diet.

B．Your quality of sleep improves.

C．You prefer healthy food to fast food.

D．There is no reason you should exercise in the morning.

E．You can keep your head clear for 4-10 hours after exercise.

F．After you exercise, you continue to burn calories throughout the day.

G．If you are planning to do exercise regularly, or you’re doing it now, then listen up!