题型:任务型阅读 题类:真题 难易度:困难
2017年高考英语真题试卷(北京卷)含听力
Every animal sleeps,but the reason for this has remained foggy. When lab rats are not allowed to sleep, they die within a month.
One idea is that sleep helps us strengthen new memories. We know that, while awake,fresh memories are recorded by reinforcing (加强)connections between brain cells, but the memory processes that take place while we sleep have been unclear.
Support is growing for a theory that sleep evolved so that connections between neurons(神经元)in the brain can be weakened overnight, making room for fresh memories to form the next day.
Now we have the most direct evidence yet that he is right. The synapses in the mice taken at the end of a period of sleep were 18 per cent smaller than those taken before sleep,showing that the connections between neurons weaken while sleeping.
If Tononi's theory is right, it would explain why, when we miss a night's, we find it harder the next day to concentrate and learn new information —our brains may have smaller room for new experiences.
Their research also suggests how we may build lasting memories over time even though the synapscs become thinner. The team discovered that some synapses seem to be protected and stayed the same size. “You keep what matters,” Tononi says.
A. We should also try to sleep well the night before. B. Ti's as if the brain is preserving its most important memories. C. Similarly, when people go for a few days without sleeping, they get sick. D. The processes take place to stop our brains becoming loaded with memories. E. That's why students do better in tests if they get a chance to sleep after learning. F. “Sleep is the price we pay for learning,” says Giulio Tononi, who developed the idea. G. Tononi's team measured the size of these connections, or synapses, in the brains of 12 mice. |
Ways to protect eyes from screens
Too much screen time may cause serious eye strain(眼疲劳) and even a sharp decline of eyesight. That's a big problem a lot of people are faced with nowadays, especially those who work on a computer. The following tips may be helpful.
Get regular eye tests.
Experts recommend having a comprehensive eye exam every year to detect (探测) problems before they develop. During this test, you should tell the doctor how often you use your phone and your computer. {#blank#}1{#/blank#}Tell your doctor about it, and your eyes can be tested more accurately at that distance.
Give your eyes space
{#blank#}2{#/blank#} Studies on computer-related eye strain suggest that screens should be no closer than 40cm from your face. If this makes it hard for you to read, consider increasing the size of the text rather than moving the screen closer.
Take breaks
This may not always be practical if you're quite busy, but it's important not to stare directly at a screen for too long. {#blank#}3{#/blank#} While surveys have shown that many office workers take no more than half an hour a day away from their computer, it's recommended that you take a 15-minute break after every two hours spent at your screen.
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Staring at a screen continuously for hours on end may make it difficult for you to focus. To avoid this, many eye experts recommend the “20-20-20 rule” --looking away from your phone/computer screen every 20 minutes and focusing on an object at least 20 feet away for at least 20 seconds. The science behind his trick is that looking at objects at a distance relaxes the focusing muscle in the eye. {#blank#}5{#/blank#}.
A. Exercise your eyes. B. Give your eyes a chance to rest. C. Make your screen more eye-friendly D. Studies show it's an effective way to reduce tiredness. E. You should also measure the distance from your eyes to your screen at work. F. The closer your phone/computer screen is to your eyes, the harder they have to work to focus. G. Make sure that you use your phone or computer in a room where the lighting is bright enough. |
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