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Finding fish is going to get harder as climate change continues to heat the world's oceans. A new study finds that warming seas over the past 80 years have reduced the sustainable catch of 80 species of fish and shellfish. The sustainable catch refers to the amount of some species that can be harvested without doing long-term damage to the health of populations.

Overfishing has made that decline worse, researchers say. Overfishing refers to catching so many fish that the size of the population falls. In some parts of the world, such as the heavily fished Sea of Japan, the decrease is as high as 35 percent. That's a loss of more than one in every three fish.

Researchers examined changes in 235 populations of fish and shellfish between 1930 and 2010. Those fish populations spread far apart across 38 ocean regions. Temperature changes varied from one ocean site to another. But on average over that time, Earth's sea-surface temperatures have risen by about half a degree Celsius.

On average, that warming had caused the sustainable catch to drop by 4.1 percent, the study found. About 8 percent of the fish and shellfish populations the team studied saw losses as a result of the ocean warming. However, about 4 percent of some populations increased. That's because certain species have thrived in warmer waters. One example is a kind of black sea fish. It lives along the northeastern U.S. coast. As warming continues, these fish will reproduce faster until they reach their limit.

About 3.2 billion people worldwide rely on seafood as a source of food. That means it's urgent for commercial fishing fleets(捕鱼船队) and regulators(监管机构) to consider how climate change is affecting the health of all of those fish in the sea.

Many of the Earth's creatures die because of humans' choices. These choices have nothing to do with food or shelter or anything else that helps humans survive. What kills millions of animals all over the world is that humans want to make money by doing so.

People use parts of animals for everything from hats to handbags, from jewelry to ashtrays(烟灰缸) and to make powders that supposedly improve a person's life. Deciding that a species is endangered and protecting it by law are not always enough. People who kill wildlife illegally rarely get caught.

During the late 1980s, saving elephants became a popular cause. Wildlife protection groups made sure everyone saw pictures or films of elephants with their faces cut off for their ivory. These groups also proved that certain populations of elephants were decreasing. As a result, most people stopped buying objects made of ivory. Laws against poaching (偷猎) were made stronger. Many countries made importing ivory illegal. Killing elephants for their ivory became more risky and less profitable.

However, concern for certain species will become weak after a while. In the late 1970s, people protested against the killing of seal babies. Everyone was shocked to see young seals being killed in their icy habitat. The cruel activity stopped. But ten years later, the number of killed seal babies was higher than ever.

Other animal protection movements have come and gone, such as saving the whales and protecting dolphins. The whale population appears to have increased for now. And the laws are finally changed in America to protect the dolphins that swim with tuna fish in parts of the Pacific Ocean.

In the years to come, people's attention will probably turn to some other endangered species. Plenty of them urgently need attention.During this time, will the elephants be forgotten? 

Snow leopards (豹) are so hard to photograph that scientists aren't even sure how many of these endangered animals still live in the wild.

The Snow Leopard Conservancy(SLC) set up 20 cameras in Russia in 2010 to learn more about the big cat. After a full six months, they had exactly zero picture! That's when the organization understood they needed help. And the only people who could help them in finding the leopards were the very people from whom they wanted to protect the animals—local hunters.

Hunting snow leopards is against the law in Russia, but in the terrible climate of Siberia, the few people living there had to turn to poaching (偷猎) to feed their families.

In 2013, Russian naturalist Sergei Spitsyn approached Mergen Markov, a local hunter, and told him his project. Markov agreed to set up the camera where he knew he would find leopards, and it worked. 

Markov, once a poacher, works full time for the conservationists now and has 10 cameras monitoring leopards. "I visit each camera once a month. I have known this whole region since I was a child," he said proudly.

The World Wide Fund For Nature (WWF) began working with other local villagers in 2015. The village would be paid 40,000 rubles(卢布)at the end of the year if the image of a snow leopard is caught. The WWF also rents horses from the villagers so that they do not need to make money by poaching anymore. "Today there are far fewer leopard poachers but leopards still get caught in traps set for other animals, so I have to stay watchful," said Markov.

Changing guns for cameras has made a big difference in the lives of these former poachers, the village, and the Russian snow leopards. The number of snow leopards has been rising and their population is expected to recover to normal levels within 10 years.

Help Hermit Crabs(寄居蟹)

Hermit crabs are nature's recyclers. They eat waste and help keep the ocean and shores clean. Unlike other crabs,the hermit crab has a thin outer shell over its soft tail. This makes the hermit crab easy prey for hungry attackers. Hermit crabs stay safe by living in old seashells. A hermit crab is picky(挑剔的);it tries on many shells until it finds one that fits just right. In recent years,however,many hermit crabs have had trouble finding their perfect homes. What is the problem?There are not enough shells to go around!

One reason for the seashell shortage is that ocean water is not as clean as it once was. This has caused chemical changes to sea water. Some sea animals,like snails,are affected by these changes. Now there are fewer snails making shells. People visiting the beach often take shells home as souvenirs(纪念品). This is another problem. Other people even hunt and take shells for their own pet hermit crabs! They do not realize that hermit crabs in the wild need those shells, too.

Now people are aware of that and working to solve this hermit crab housing shortage. They are teaching beach-Boers to leave seashells where they belong—at the seashore! Some people even make fake seashells that they hope the hermit crab will like. For example,a group called Project Shelter invited people who visited their website to create different designs for hermit crab shells.

These designers had a lot to consider. What kind of material should be used to build seashells?The material must be light enough for the hermit crab to carry,but strong enough to protect the crab from attackers. The man-made shells could not contain glue or any other substance(物质) that might harm the hermit crab. Another challenge of building a hermit crab home was the opening of the shell. Too big would mean the crab would not feel safe. Too small would be uncomfortable,and the crab would not want to move in.

The Project Shelter shells are placed in the wild for hermit crabs to find. Lucky hermit crabs can move into these new dream homes.

Once upon a time，there lived in Basra an old man.His only job was caring for and loving his only son who was a handsome young man.The old man put all his money into his son's education.The young man went away for a few years and received an education at a well－known university，where there were many scholars (学者)．

The day arrived for the son to return from his studies.When the son came and met his father，the old man looked into his eyes and felt great disappointment."What have you learnt，my son？" he asked."I have learnt everything that was to be learnt，father，" the son said.

"But have you learnt what cannot be taught？" asked the father."Go，my son and learn what cannot be taught，" said the old man.

The young man went back to ask his headmaster to teach him what cannot be taught."Go away to the mountains with these four hundred sheep and come back when they are one thousand，" said the master.

The young man went to the mountains and became a shepherd (牧羊人)．There for the first time he came across silence.He had no one to talk to.The sheep did not understand his language.Hopelessly，he would talk to them but they would look back at him as if to say he were stupid.Slowly but certainly，he began to forget all his worldly knowledge and his pride.He became quiet，wise and humble (谦逊的)．

At the end of two years，when the number of sheep had grown to one thousand，he returned to his master and fell on his knees."Now you have learnt what cannot be taught，" said the master.

The United Kingdom, Great Britain, Britain, England--many people are  (confuse) by what these different names mean. So what is the  (different) between them, if any?  (get) to know a little bit about British history will help you solve this puzzle.

In the 16th century, the nearby country of Wales was joined the Kingdom of England. Later, in the 18th century, the country Scotland was joined (create) the Kingdom of Great Britain. In the 19th century, the Kingdom of Ireland was added to create the United Kingdom of Great Britain and Ireland. (final), in the 20th century , the southern part of Ireland (break) away from the UK, which resulted the full name we have today: the United Kingdom of Great Britain and Northern Ireland. Most people just use the shortened name: "the United Kingdom" or "the UK". People from the UK are called "British", means the UK is also often (refer) to as Britain or Great Britain.