Life in the Clear
Transparent animals let light pass through their bodies the same way light passes through a window. These animals typically live between the surface of the ocean and a depth of about 3,300 feet-as far as most light can reach. Most of them are extremely delicate and can be damaged by a simple touch. Sonke Johnsen, a scientist in biology, says, “These animals live through their life alone. They never touch anything unless they’re eating it, or unless something is eating them.”
And they are as clear as glass. How does an animal become see-through? Ifs trickier than you might think.
The objects around you are visible because they interact with light. Light typically travels in a straight line. But some materials slow and scalier(散射) light bouncing it away from its original path. Others absorb light, stopping it dead in its tracks. Both scattering and absorption make a.n object look different from other objects around it, so you can see it easily.
But a transparent object doesn't absorb or scatter light, at least not very much. Light can pass through it without bending or stopping. That means a transparent object doesn't look very different from the surrounding air or water. You don't see it- you see the things behind it.
To become transparent, an animal needs to keep its body from absorbing or scattering light. Living materials can stop light because they contain pigments(色素) that absorb specific colors of light. But a transparent animal doesn’t have pigments, so its tissues won’t absorb light. According to Johnsen, avoiding absorption is actually easy. The real challenge is preventing light from scattering.
Animals are built of many different materials—skin, fat, and more—and light moves through each at a different speed. Every time light moves into a material with a new speed, it bends and scatters. Transparent animals use different tricks to fight scattering. Some animals are simply very small or extremely flat. Without much tissue to scatter light, it is easier to be see-through. Others build a large, clear mass of non-living jelly-like(果冻状的) material and spread themselves over it.
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The Theobroma Cacao tree, to use its scientific name, provides us with one of the world's most delicious foods—chocolate! Theobroma is a Greek word meaning 4food of the gods. The tree originally comes from the Amazon region of South America. Hand-sized pods that grow on the tree contain cacao seeds—often called ‘cocoa beans’. These seeds，or beans，are used to make chocolate.
The earliest use and consumption of cacao beans dates back to around 1000 B.C. Later, the Mayan and Aztec civilizations consumed cacao as a drink. They often flavored it with ingredients such as chili peppers, and other spices. It is believed that drinking cups of chocolate was important in Mayan rituals such as wedding ceremonies. Consuming cacao was also believed to have positive effects on health. In Peru, eating or drinking a mixture of chocolate and chili was said to be good for the stomach. The Aztecs thought it could even cure sicknesses!
Christopher Columbus, along with Spanish explorers, made his fourth voyage across the Atlantic in the early 1500s, and arrived on the coast of Honduras. It was at this time that he first discovered the value of cocoa beans，which were used as currency in many parts of Central America.
In the sixteenth century, chocolate was taken back to Spain by Hernando Cortez, another explorer. The Spanish people added ingredients such as sugar and vanilla to make it sweet. It later spread to France in the seventeenth century. The popularity of chocolate continued to spread further across Europe and the Americas. The only Asian country to adopt it at that time, though, was the Philippines, which the Spanish invaded in the sixteenth century.
As chocolate became more popular, the demand for people to work on the cocoa plantations increased. Slaves were brought to the Americas from Africa to farm the cocoa. Eventually, the cacao tree was taken to
Africa and cultivation(m) began there. Today, the African plantations provide almost seventy percent of the world's cacao, compared with one and a half percent from Mexico.
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People think animals are stupid, that they don’t understand kindness and that they can’t feel trust, or gratitude, or love. But I know they’re wrong and I have the evidence I need. It happened on a winter night, when a duck climbed up the stairs to save his sister.
That day, the temperature had suddenly dropped sharply, with cold winds blowing strongly and big snow falling. It wasn’t until late afternoon that we remembered our two ducks were still at our poorly built small farm. “Have they died due to the cold?” we wondered, worried.
My mother and I hurried to the farm and luckily found they were still alive. Their body was covered with snow; they were too cold to even quack. They stayed close together for warmth. We decided to take them home. Once back in the warm house, we made a nest for them in the basement, using newspaper and towels, and brought them food and water. The ducks gathered together in the warm basement. Near their nest, there were fishing nets we had carelessly left. We didn’t realize that could be a danger to them.
We just decided to leave the ducks alone to warm up and recover. We knew they had enough food and water, so we didn’t go down to the basement again that afternoon. That evening we were reading by the fire in the living room when we heard a strange sound coming from the basement. There was kind of a strange noise, then a pause (停顿), and then the strange sound again-over and over.
“Could that be the ducks?” my mother asked my father. Curious about that, we stood up and went to find out. It was indeed the ducks- at least one of them. We found the duck brother was standing on the second-highest step, beating his wings for balance. He gathered his strength and made the difficult leap to the highest step, the source of the strange noise
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When he saw us, he stayed there and started quacking (呱呱叫) crazily and beating his wings.
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To free the duck sister from the fishing nets, I rushed upwards to bring scissors.
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Every Dog Has Its Day
Roscoe was a big, ugly bulldog. He wasn’t very smart, but he had a good heart. Roscoe’s owner left him chained up outside each day when he went to work. Roscoe liked being outside. He was always nice to everyone. He didn’t even bother the rat that lived in a nearby hole.
A group of boys often passed Roscoe on their way to and from school. One day, one of the boys had a candy bar in his hand as he walked by. Roscoe jumped up when he smelled that candy bar. He tried to run over to the boy, but his chain stopped him short. The boys all laughed when they saw Roscoe pulling on his chain. The boy with the candy bar held it in front of Roscoe’s nose. He kept it just out of reach to tease him. All the boys laughed as Roscoe tried to reach the candy bar but couldn’t.
From then on, those boys never passed Roscoe without doing something mean to him. Poor Roscoe was having a hard time and felt scared. The rat that lived in the alley had been watching. She understood that people were sometimes mean to animals for no good reason. She didn’t think it was nice. She decided to help Roscoe.
When Roscoe went to sleep for his afternoon nap, she quietly sneaked over to him. She began chewing on Roscoe’s leather collar around his neck which the chain was connected to. She had chewed through more than half of it when she heard out voices down the alley.
The rat raced back into her hole and saw that the boys were coming. Roscoe was awake now. When the boys saw him, they laughed and started throwing sticks at him. Roscoe was hit and he barked angrily at the boys with all his strength. This time when he got to the end of his chain, his collar broke off. He was free.
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1.所续写短文的词数应为75左右；
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The boys ran off as fast as they could, but one of them slipped and fell.
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Judging from recent surveys, most experts in sleep behavior agree that there is virtually an epidemic of sleepiness in the nation.“I can’t think of a single study that hasn’t found Americans getting less sleep than they ought to,” says Dr. David. Even people who think they are sleeping enough would probably be better off with more rest.
The beginning of our sleep-deficit crisis can be traced back to the invention of the light bulb a century ago.From diary entries and our personal accounts from the 18th and 19th centuries, sleep scientists have reached the conclusion that the average person used to sleep about 9.5 hours a night.”The best sleep habits once were forced on us, when we had nothing to do in the evening down on the farm, and it was dark.” By the 1950s and 1960s, the sleep schedule had been reduced dramatically, to between 7.5 and 8 hours, and most people had to wake to an alarm clock. “People cheat in their sleep, and they don’t even realize they’re doing it,” says Dr. David, ”They think they’re okay because they can get by on 6.5 hours, when they really need 7.5, 8 or even more to feel ideally vigorous.”
Perhaps the most merciless robber of sleep, researchers say, is the complexity of the day. Whenever pressures from work, family, friends and community increase, many people consider sleep the least expensive item on their program.” In our society, you’re considered dynamic if you say you need only 5.5 hours’ sleep. If you’ve got to get 8.5 hours, people think you lack drive and ambition.”
To determine the consequences of sleep-deficit, researchers have put subjects through a set of psychological and performance tests requiring them, for instance, to add columns of numbers or recall a passage read to them only minutes earlier. “We’ve found that if you’re in sleep deficit, performance suffers,” says Dr. David, ”Short-term memory is weakened, as are abilities to make decisions and to concentrate.”
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Wearable technology can reportedly tell you a lot more than just the number of calories you’re burning or how many steps you’ve walked… That clever smartwatch can actually tell that you’re about to get a cold, days before you start feeling poorly. As New Scientist reports, researchers at Stanford University in California have discovered that wearable tech can now detect when you’re about to fall prey to (感染) a frightening winter bug, simply by tracking your vital statistics.
After monitoring 40 smartwatch users for up to two years, the team has demonstrated that the devices can be used to detect the first signs of coming illness. The participants’ pulse and skin temperature were continuously monitored throughout the period, with the scientists noting that their smartwatches recorded unusually higher heart rates and skin temperatures up to three days before the volunteers began displaying symptoms of cold or flu.
Study leader Michael Snynder said: “Once these wearables collect enough data to know what your normal baseline readings are, they can get very good at sensing when something goes wrong. We think that if your heart rate and skin temperature are elevated for about two hours, there’s a strong chance you’re getting sick.” “Continuous tracking of your vital signs is more informative than having a doctor measure them once a year and comparing them with population averages,” he added.
The team now hopes to create an algorithm (算法) that will let smartwatches notify you when you’re about to get sick. Well, at least that might give us the chance to stock up on vitamins and wrap up warm before the germ attacks!
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The lost art of listening
Do you think you’re a good listener? Chances are that you do. But studies show that most people seriously overestimate their ability to listen. The truth is we are generally not good at listening, and our listening comprehension declines as we age.
This was proven by Dr. Ralph Nichols, who conducted a simple experiment to test students’ listening skills. He had some Minnesota teachers stop what they were doing mid-class, and then asked students to describe what their teachers had been talking about. While older kids with more developed brains, are usually assumed to be better listeners, the results, however, showed otherwise: While 90 percent of first-and second-graders gave correct responses, this percentage dropped rapidly as the students got older.
One reason for our poor listening concerns the speed at which we think. The adult brain can process up to around 400 words per minute, more than three times faster than the speed an average person speaks. This means we can easily think about something else while someone is talking to us, allowing our mind to wander or get sidetracked. The younger students in Dr. Nichols’s experiment were better listeners partly because their brains were less developed — they lacked the extra brain power to be distracted.
Another factor that contributes to our poor listening is our ever-decreasing attention span. According to a Mircrosoft study, the age of smartphones has had a negative impact here. In 2000 — around the time the mobile revolution began — the average human attention span was 12 seconds; by 2013, it had fallen to 8 seconds. Even a goldfish — with an average attention span of 9 seconds — can hold a thought for longer!
More and more people now realize that listening is a skill that can be developed through practice. Learning to observe a speaker’s body language and emotions, for example, can improve our active listening. Even the simple act of note-taking or making eye contact can help us stay focused while listening.
