牛津译林版（2019）必修第二册 Unit 2 Be sporty be healthy课后习题Section B

These animals at such a high speed that they will disappear soon.

Let's hand in the exercises earlier .

It is said that the problem .

She has the opportunity by people all over the world.

I feel very shocked that the window of our classroom .

People donate large sums the appeal for the victims of the earthquake.

She couldn't attend the meeting so her assistant.

For those who can stomach it, working out before breakfast may be more beneficial for health than eating first, according to a study of meal timing and physical activity.

Athletes and scientists have long known that meal timing affects performance. However, far less has been known about how meal timing and exercise might affect general health.

To find out, British scientists conducted a study. They first found 10 overweight and inactive but otherwise healthy young men, whose lifestyles are, for better and worse, representative of those of most of us. They tested the men's fitness and resting metabolic (新陈代谢的) rates and took samples (样品) of their blood and fat tissue.

Then, on two separate morning visits to the scientists' lab, each man walked for an hour at an average speed that, in theory, should allow his body to rely mainly on fat for fuel. Before one of these workouts, the men skipped breakfast, meaning that they exercised on a completely empty stomach after a long overnight fast (禁食). On the other occasion, they ate a rich morning meal about two hours before they started walking.

Just before and an hour after each workout, the scientists took additional samples of the men's blood and fat tissue.

Then they compared the samples. There were considerable differences. Most obviously, the men displayed lower blood sugar levels at the start of their workouts when they had skipped breakfast than when they had eaten. As a result, they burned more fat during walks on an empty stomach than when they had eaten first. On the other hand, they burned slightly more calories (卡路里), on average, during the workout after breakfast than after fasting.

But it was the effects deep within the fat cells that may have been the most significant, the researchers found. Multiple genes behaved differently, depending on whether someone had eaten or not before walking. Many of these genes produce proteins (蛋白质) that can improve blood sugar regulation and insulin (胰岛素) levels throughout the body and so are associated with improved metabolic health. These genes were much more active when the men had fasted before exercise than when they had breakfasted.

The implication of these results is that to gain the greatest health benefits from exercise, it may be wise to skip eating first.

It's 6:15 am on a school day, and Jocelyn Murzycki has two kids and she needs to get out the door in an hour. As the sky begins to1, Murzycki doesn't manage a few more minutes of sleep.2, she's heading out in the freezing cold on her daily plog—a run to3litter.

First, the4are:a litter grabber and a reusable shopping bag, one side for landfill and the other for5. Covering herself up, Murzycki jogs6down Main Street, stopping briefly to pick up a plastic cup. She usually needs to stop halfway through her 20-minute run to7her bag. Within a few hours the street will look littered again. But she isn't8—it just adds fuel to her plogging fire.

The word "plogging" comes from plogga, a9of two Swedish words that mean to pick up and to jog. The activity was10by Erik Ahlstrom. When he moved to Stockholm, he felt11at the amount of litter in the streets and began gathering friends to clean up the neighborhood while out for runs. Now Mr. Ahlstrom is traveling the world, publicizing the12of plogging. In the U. S. , social media and running groups are13people to get out and plog:the "plogging" tag (标签) alone has more than 40, 000 posts.

Murzycki has been doing this for a few years even before the trend hit the U. S. "It is really super14if you go out every single day and just pick up litter, " she says. But she has figured out how to make it fun by jogging with friends and adding the15in which finding a tiny glass bottle adds one push-up (俯卧撑).

Want to blow out all the candles on your cake when you're 75 or climb stairs without feeling out of breath at the top?.

Breatheinthroughyournose

When it's hot and dry or very cold, or you're in a dusty or polluted environment, try to breathe through your nose and breathe out through your mouth. Our noses filter(过滤) the air we breathe and control its temperature. .

Dosimpleworkoutsthatimproveyourlungs

Try this easy exercise to help increase your lung capacity (容量):lie on your back with knees bent and feet flat on the floor. Put your hands behind your head and bring your elbows(肘部) together so that they nearly touch. . Then your arms are flat on the floor when your lungs are full. When you breathe out, raise your elbows again.

Wearafacemasktodoworkaroundthehouse

. But if you are using them, make sure you wear a face mask to prevent dangerous gases reaching your lungs. Make sure your windows are open at the same time and keep the air in the room fresh.

A study from the University of Nottingham found that people who ate more than five apples a week had improved lung function. And eating more oily fish can help reduce inflammation (炎症), which is linked to lung problems.