【推荐1】It was a village in India. The people were poor. However, they were not unhappy. After all, their forefathers had lived in the same way for centuries.

Then one day, some visitors from the city arrived. They told the villagers there were some people elsewhere who liked to eat frog’s legs. However, they did not have enough frogs of their own, and so they wanted to buy frogs from other places.

This seemed like money for nothing. There were millions of frogs in the fields around, and they were no use to the villagers. All they had to do was catch them. Agreement was reached, and the children were sent into the fields to catch frogs. Every week a truck arrived to collect the catch and hand over the money. For the first time, the people were able to dream of a better future. But the dream didn’t last long.

The change was hardly noticed at first, but it seemed as if the crops were not doing so well. More worrying was that the children fell ill more often, and, there seemed to be more insects around lately.

The villagers decided that they couldn’t just wait to see the crops failing and the children getting weak. They would have to use the money earned to buy pesticide and medicines. Soon there was no money left.

Then the people realized what was happening. It was the frog. They hadn’t been useless. They had been doing an important job—eating insects. Now with so many frogs killed, the insects were increasing more rapidly. They were damaging the crops and spreading diseases.

Now, the people are still poor. But in the evenings they sit in the village square and listen to sounds of insects and frogs. These sounds of the night now have a much deeper meaning.

【推荐3】There have been numerous wake-up calls about the effects of climate change on sea life. As ocean waters heat up, they are making coral lose color. Growing levels of carbon dioxide are making seawater more acidic. Now climate change is starting to affect fish's sense of smell, a phenomenon that will worsen in the coming years if global warming continues growing.

A sense of smell is what the fish can't do without. They use it to find food, detect upcoming danger, escape from predators (捕食者）find safe environments, and even recognize one another. "Future levels of carbon dioxide can have large negative effects on the sense of smell of fish, which can affect fish population numbers and the entire ecosystem, ”said an ocean life expert. "This can be prevented, but we must reduce carbon emissions now before it's too late.”

Experts believe that about half of carbon dioxide emissions produced by human activities, such as the burning of fossil fuels--have over time ended up in the oceans, lowering the pH of seawater, and making it more acidic.

Researchers found that sea bass (鲈鱼）exposed to the more acidic conditions swam less and were less likely to react when encountering the smell of a predator. Also, they were more likely to "freeze", a sign of anxiety, according to the study. They found the longer the fish were in high CO2,the worse they got along. The researchers also measured the ability of the fish to detect certain odors (气味）in different levels of acidity (酸度）。 The study showed that their ability to detect and respond to some odors connected with food and threatening situations was more strongly affected than other odors.

The research is important because 20 percent of the protein consumed by 3 million people comes from seafood, and about 50 percent of this comes from fish caught from the wild. “Therefore, increases in carbon dioxide in the ocean have the potential to affect all fish species, including those that many people rely on food and livelihood, "the ocean life expert warned.

【推荐1】Are you afraid of going to the dentist(牙医)?If so, you’re not alone.

These fears could just be in our heads, however. According to a recent survey by Martin Tickle, a professor at the University of Manchester in the UK, the pain isn’t felt most of the time in dental surgeries(牙科手术). In fact, among the 451 interviewed patients, 75％reported no pain at all during their visits, including situations when they had their teeth pulled out.

Could it be the sound of the drill(钻头)then?

“I found that the sound of drilling can evoke deep worry in dental patients. Actually they don’t have any pain, ”Hiroyuki Karibe, a scientist at Nippon Dental University in Tokyo, told The Guardian.

To find the reason why a drill might bring on a racing heart, Karibe divided the volunteers into low-fear and high-fear groups based on how much they feared a trip to the dentist. Volunteers were played the sound of a drill while their brain activities were watched by a machine.

What Karibe found in the low-fear group was increased activity in the areas of the brain relative to auditory processing(听觉处理), which means, for these people, the sound of dental drills is no different from other sounds.

In the high-fear group, however, the brain area that was activated(激活)was different. It was the area that carries out a number of duties, including learning, feelings and, most importantly, memory. This means that these volunteers not only heard the sound, but they remembered it——they made connections between the sound of a drill and the worry it produced in the past, causing their worry to return.

Understanding how brains reply to the sounds of dentists’ drills could help scientists find ways to make patients more relaxed, according to Karibe, because patients who worry about going to the dentist might keep putting off their visits. But the best way is to keep your teeth healthy.

【推荐2】Teenagers are risk-takers. Those things may not be understood by the adults around them. Are they driven by poor judgment or immature (不成熟的)brains?

In their book Wildhood, the bestselling authors Barbara Natterson-Horowitz and Kathryn Bowers, present findings from their five-year study on wild animal adolescence(青春期). The two performed a complete survey of age-related   death in wild animals and found something   truly surprising—young folks are born to take risks, and with good reasons.

Life on Earth for adolescent and young adult animals is just as dangerous. In the wild young animals crash, drown and starve more often than their adult animals. And they are more likely to be targeted and killed by predators (捕食者).Old enough to be away from home? But new to the ways of the world? This time of life is risky for human adolescents as well. Wildlife biologists describe these unprepared creatures as predator naives(幼稚).

Facing death danger while still maturing is a fact of life for adolescents across species. Adolescents must have predator awareness if they are to survive. Said another way: To become safe, you must take risks.

Adult bats typically flee predators such as barn owls. But adolescent bats have been seen doing the opposite —flying toward them. This behavior can also be seen in other wild animals. Biologists call it “predator inspection(检查)”. Predator inspection provides young animals important information about their deadly predators. Familiarity with predatory strategies helps adolescents survive and even avoid future attacks. Predator inspection is one of the ways to help predator naives to become experienced predators.

Studying wild animal adolescence offers a new understanding of why teenagers act the way they do. Parents should balance the urge to protect with the need to let their teenagers test their wings. The research suggests that adolescents need some exposure to the dangers they will someday face on their own —and without knowing that, parents’ over protection maybe the riskiest behavior of all.

【推荐3】Weather influences health, intelligence and feelings.     1    

In August, it is very hot and wet in the southern part of the United States.     2     In the northeast and the middle west, it is very hot at some times and very cold at other times. People in these states have more heart trouble after the weather changes in February or March.

    3     For example, in a recent report by scientists, IQ of a group of students was high when a very strong wind came, but after the strong wind, their IQ was 10% lower. The wind can help people have higher intelligence. Very hot weather, on the other hand, can make it lower. Students in many schools of the United States often get worse on exams in the hot months of the year.

Weather also has a strong influence on people’s feelings. Winter may be a bad time for thin people. They usually feel cold during these months. They might feel unhappy during cold weather.     4     Generally speaking, at about 18℃, people become stronger and better. Low air temperature may make people forgetful. People leave more bags on buses and in shops in cold days.

    5     Sometimes, it may be the weather’s problem.

【推荐1】There are hundreds of types of birthday cake in the world. You are likely to enjoy one during at least one of your birthday parties. But have you ever stopped and wondered, “Why am I eating this? What makes this dessert fit to celebrate the day of my birth?”

It’s because you are as important and beloved as the gods.

The ancient Egyptians are thought to have “invented” the celebration of birthdays. They believed when pharaohs (法老) were crowned, they became gods, so their coronation (加冕) day was their “birth” as a god.

Ancient Greeks borrowed the tradition, but realized that a dessert would make the celebration more meaningful. So they baked moon-shaped cakes to offer up to the goddess of the moon. They decorated them with lighted candles to make the cakes shine like the moon. It is the reason why we light our birthday cakes on fire.

Modern birthday parties are said to get their roots from an 18th century German celebration. On the morning of a child’s birthday, he or she would receive a cake with lighted candles that added up to the kid’s age, plus one. This extra candle was called the “light of life,” representing the hope of another full year lived.

And then, torture — because no one could eat the cake until after dinner. The family replaced the candles as they burned out throughout the day. Finally, when the moment came, the birthday child would make a wish, try to blow out all the candles in one breath, and dig in.

Since the ingredients (原料) to make cakes were pretty expensive, this birthday custom didn’t become popular until the Industrial Revolution. More ingredients were available, which made them cheaper, and bakeries even started selling pre-baked cakes.