1.学生近视率状况描述；
2.简单评论；
3.你的建议。
1.词数80左右；
2.短文题目和首句已为你写好，不计入总词数。
Protecting our eyes to enjoy a bright world
The health of children’s vision is facing a growing threat.
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2 . Eyesight plays a very important role in our daily life. Every waking moment, the eyes are working to see the world around us. Over forty percent of Americans worry about losing eyesight, but it's easy to include steps into our daily life to ensure healthy eyes. Here are five suggestions for a lifetime of healthy eyesight:
Schedule yearly exams.
Protect against UV rays .
Long-term stay in the sun creates risk to your eyes. No matter what the season is, it’s extremely important to wear sunglasses.
Two-thirds of Americans spend up to seven hours a day using computers or other digital products.
As part of a healthy diet, eat more fruits and vegetables each day. Vitamins C and E help protect eyesight and promote eye health.
Practice safe wear and care of contact lenses.
Many Americans use contact lenses to improve their eyesight. While some follow the medical guidance for wearing contact lenses, many are breaking the rules and putting their eyesight at risk.
Otherwise: you may have problems such as red eyes, pain in the eyes, or a more serious condition.
| A．Eat your greens. |
| B．Eye care should begin early in life. |
| C．They can properly protect your eyes. |
| D．Stay in good shape by taking more vitamins. |
| E．Parents usually don’t care about their own eyesight. |
| F．Always follow the doctor’s advice for appropriate wear. |
| G．This frequent eye activity increases the risk for eye tiredness. |
If blood is red, why are veins (静脉) blue?
Actually, veins are not blue at all. They are more of a clear, yellowish color. Although blood looks red when it’s outside the body, when it’s sitting in a vein near the surface of the skin, it’s more of a dark reddish purple color. At the right depth, these blood-filled veins reflect less red light than the surrounding skin, making them look blue by comparison.
Which works harder, your heart or your brain?
That kind of depends on whether you’re busy thinking or busy exercising. Your heart works up to three times harder during exercise, and shifts enough blood over a lifetime to fill a supertanker (超级油轮). But, in the long run, your brain probably tips it, because even when you’re sitting still your brain is using twice as much energy as your heart, and it takes four to five times as much blood to feed it.
Why do teeth fall out, and why don’t they grow back in grown-ups?
Baby (or “milk”) teeth do not last long; they fall out to make bigger room for bigger, stronger adult teeth later on. Adult teeth fall out when they become damaged, decayed (腐烂) and infected by bacteria. Once this second set of teeth has grown in, you’re done. When they’re gone, they are gone. This is because nature figures you’re set for life, and what controls regrowth of your teeth switches off.
Do old people shrink (收缩) as they age?
Yes and no. Many people do get shorter as they age. But, when they do, it isn’t because they’re shrinking all over. They simply lose height as their spine (脊柱) becomes shorter and more curved due to disuse and the effect of gravity (重力). Many (but not all) men and women do lose height as they get older. Men lose an average of 3-4 cm in height as they age, while women may lose 5 cm or more. If you live to be 200 years old, would you keep shrinking till you were, like 60 cm tall, like a little boy again? No, because old people don’t really shrink! It is not that they are growing backwards—their legs, arms and backbones getting shorter. When they do get shorter, it’s because the spine has shortened a little. Or, more often, become more bent and curved.
Why does spinning make you dizzy?
Because your brain gets confused between what you’re seeing and what you’re feeling. The brain senses that you’re spinning using special gravity-and-motion-sensing organs in your inner ear, which work together with your eyes to keep your vision balance stable. But when you suddenly stop spinning the system goes out of control, and your brain thinks you’re moving while you’re not.
Where do feelings and emotions come from?
Mostly from an ancient part of the brain called the limbic system (边缘系统). All mammals have this brain area—from mice to dogs, cats, and humans. So all mammals feel basic emotions like fear, pain and pleasure. But since human feelings also involve other, newer bits of the brain, we feel more complex emotions than any other animal on this planet.
If exercise wears you out, how can it be good for you?
1. What is the color of blood in a vein near the surface of the skin?
| A．Blue. | B．Light yellow. |
| C．Red. | D．Dark reddish purple. |
| A．Because their spine is in active use. |
| B．Because they are more easily affected by gravity. |
| C．Because they keep growing backwards. |
| D．Because their spine becomes more bent. |
| A．In the long run, our brain probably works harder than our heart. |
| B．When our brain senses the spinning, we will feel dizzy. |
| C．The brains of the other mammals are as complex as those of humans. |
| D．Our feelings and emotions come from the most developed area in our brain. |
| A．To give advice on how to stay healthy. |
| B．To provide information about our body. |
| C．To challenge new findings in medical research. |
| D．To report the latest discoveries in medical science. |
