2 . In habitats across the planet, animals periodically drop everything to walk, fly or swim to a new place. Some animals such as whales and geese learn migration paths by following their parents. Others, including small songbirds, gain the distance and direction of their migration within their genetic code. And some animals use a combination of genetics and culture to guide their migration.

Another group of migrators does not quite fit either model, and researchers have only recently started to figure out how they find their way. The Cory’s shearwater is an oceangoing seabird that migrates over the Atlantic every year. The young do not migrate with their parents, so culture cannot explain their journeys. And the exact paths vary wildly from individual to individual, making genetics equally unlikely.

Cory’s shearwaters are long-lived, rarely producing young successfully before age nine. This leaves an opening for learning and practice to develop their migration patterns. Researchers call this the “exploration-refinement”, and until now it has been hypothetical (假设的) because of difficulties in tracking migratory animals’ movements.

But a team of researchers has done that by attaching small geolocators to more than 150 of the birds aged four to nine. They found that younger birds traveled longer distances, for longer periods, and had more diverse paths than older birds. “We finally have evidence of the ‘exploration-refinement’ for migratory birds,” says Letizia Campioni, who led the study. Younger Cory’s shearwaters are able to fly just as fast as the adults——but they do not, suggesting that the young do more exploring, which gradually fades as they mature and settle into a preferred course.

“Although it may seem less efficient than other strategies, exploration refinement could be beneficial to birds and other organisms in a rapidly changing world due to unpredictable man-made changes,” says Barbara Frei. “It might be safer to repeat a behavior that was recently successful than to rely on patterns that were perfected long ago but might no longer be safe.”

3 . An earthquake can strike without warning. But many injuries and deaths from this kind of natural disaster can be prevented if people follow these safety tips.

If you’re inside a building, stay there! One of the most dangerous things to do in an earthquake is to try to leave a building.     1     Drop down onto the ground. Get under an object that is not easily damaged. Hold on to it until the shaking stops. You can also get to a corner formed by two walls with your arms over your head. If you’re in bed when the quake hits, stay there and protect your head with a pillow.

    2     Don’t take shelter under trees, streetlights, telegraph poles or tall buildings. If you are driving stop as quickly as possible and stay away from overpasses, buildings, bridges or anything else that might fall or collapse over you.     3    

If you are trapped in the ruins, cover your mouth with a handkerchief or a piece of clothing. Use your cellphone to call for help if possible. Don’t shout.     4     Tap on a pipe or the wall so rescuers can find you.

Be prepared for aftershocks    5     However, sometimes they even happen months later. Therefore, if you are not in a safe position after the first shock, you should move quickly but carefully to a safer place.

4 . On Saturday 24 August 1918, it was raining cats and dogs and thundering over a city called Sunderland on the northeast coast of England. The storm lasted for only about ten minutes. People were surprised to see that it was not just rainwater falling from the sky. There were fish falling down, too! People came out to find out what was happening. They could not believe their own eyes. There were thousands of fish—sand eels (沙鳗)—lying on the ground. They were about seven centimeters long, and all were frozen solid (冻成硬块).

Sand eels swim together in large groups, often in sandy water, and are often found in large numbers in the North Sea, which reaches out to the east of Sunderland. How was it possible for these sand eels to fall from the sky and land on Sunderland?

Scientists believed the heavy thunderstorm that afternoon may have caused a waterspout (水龙卷). Waterspouts can be formed when strong winds move quickly in a circle over water. They are so powerful that anything less than one meter in length can be taken into them and forced into the clouds. The clouds carry whatever has been taken into them for long distances —sometimes over 150 kilometers. It’s very cold up there and everything soon freezes solid.

For hundreds of years there have been reports of small animals being taken into the sky through waterspouts. In 2009, dead tadpoles rained down on the city of Nanao in Japan. In 2012, fifty kilos of prawns fell from the sky over Sri Lanka. In 2017, fish fell on the coastal city of Tampico in Mexico.

It must be a very strange experience to see fish raining down on you. It would probably hurt if one fell on your head! With climate (气候) change and many reports of terrible storms, will the time ever come when it may really begin to rain cats and dogs?

Earth Day is an event    1    (annual) celebrated on April 22.     2    (found) by Senator Gaylord Nelson, an American politician and environmentalist, it was originally aimed at helping the public to know the current situation of air and water pollution and    3     (get) people to care about the earth.

In1962, Rachel Carson’s bestselling book “Silent Spring” created an    4    (aware) of the dangerous effects of pesticides (农药) . Then, a fire,     5     broke out in 1969 on Cleveland’s Guyahoga River, shed light on the problem of chemical pollution in water. Senator Gaylord Nelson dreamed of    6    similar large event that would get people to take environmental issues seriously. In 1969, he was inspired by protests against the Vietnam War and came up with the idea for Earth Day.

In the fall of 1969, Nelson announced it and appealed to the entire country to get involved. Consequently, telegrams, letters and telephone calls    7    all over the country poured in. Since 1970, Earth Day celebration have grown. Later, Nelson    8    (award) the Presidential Medal of Freedom in recognition of his work.

Today, Earth Day is celebrated around the world every April 22. Sometimes numerous communities celebrate Earth Week, an entire week of    9    (activity) focused on the Environmental issues. In 2017, the March for Science    10    (occur) on Earth Day(April 22, 2017) and was followed by the People’s Climate Mobilization (April 29, 2017).

The fresh thin air, snow-covered mountains and graceful animals running on the plains are     1    we’re here-to observe Tibetan antelopes, which are being hunted,     2    (legal), for their valuable fur.

My guide is Zhaxi, who works at the Changtang National Nature Reserve. “We’re not trying to save the animals,”he says. “Actually, we’re trying to save     3    (we).”

As    7    result, the antelope population has recovered and in June 2015, the Tibetan antelope was removed from the     8     (danger) species list. The govermment, however, does not intend    9    (stop) the protection programmes, since the threats to the Tibetan antelope have not yet disappeared.

   Only when we learn to live in harmony with nature     10     we stop being a threat to wildlife and to our planet.

7 . A five-year-old dog named Kelsey has been praised as a hero for helping to save the life of her owner who slipped in the snow and broke his neck.

The man, Bob, was alone when he left his Michigan farm house on New Year’s Eve to collect firewood. Expecting a journey of only several meters, Bob was wearing just long johns (衬裤), a shirt and slippers when he went outside, although the temperature was around -4℃.

After the accident, he was unable to move in the snow. Fortunately, Kelsey came to his assistance. “I was shouting for help, but my nearest neighbor is about 400 meters away, and it was 10:30 pm,” Bob explained. “But my Kelsey came. By the next morning, my voice was gone and I couldn’t yell for help, but Kelsey didn’t stop barking.” Kelsey’s companion kept him warm by lying on top of him. She licked his face and hands to keep him awake. “Kelsey kept barking but never left my side,” Bob recalled. “She kept me warm. I knew I couldn’t give up and that it was my choice to stay alive.”

Bob spent 20 hours in the freezing cold. When he finally lost consciousness, his dog kept barking. Finally, hearing the barking, Bob’s neighbor discovered him at 6:30 pm on New Year’s Day and called the emergency services at once. When Bob arrived in hospital, his body temperature was below 21 ℃. However, doctors were surprised to find that he didn’t have any frostbite (冻疮). They believed it was because of Kelsey’s determination to keep him warm. Dr. Chaim Colen, the doctor who treated Bob, said, “Animals can help and his dog really saved him...He was very fortunate.”

Bob said, “I was very grateful to both Dr. Colen and my Kelsey. They saved my life. They are truly heroes!”

8 . The endangered pandas in the Qinling Mountains might face a new threat: the loss of their food, bamboo, which makes up 99% of their meals.

Adult pandas spend most part of the day eating bamboo and have to take in at least 40 pounds a day to stay healthy. However, a new study published in Nature Climate Change warned that they may soon find their food gone because most of the bamboo in the Qinling Mountains might disappear by the end of the century as a result of rising temperature worldwide.

A team made up of researchers from Michigan State University and the Chinese Academy of Sciences has studied the effects of climate change on the bamboo in the Qinling Mountains. They have found that bamboo is very sensitive to climate changes. “80% to 100% of the bamboo would be gone if the average temperature rises 3.5 degrees worldwide by the end of the century,” said Liu Jianguo, one of the report’s authors.

He added, “This is how much the temperature would rise by 2100 even if all countries will keep their promises in the Paris Agreement. But you know what is happening all around the world.”

In recent years, China has been trying its best to protect the endangered pandas by setting up more and bigger natural reserves.

“But it is far from enough and the endangered pandas need cooperation from the rest of the world, because their future is not just in the hands of the Chinese,” said Shirley Martin from the World Wildlife Fund but not a member of the team.

The Qinling Mountains, in the southwest of China, are home to about 260 pandas. That is about 13% of China’s wild panda population. In addition, about 375 are living in research centers and zoos in China.

10 . Scientists say a huge percentage of bird species are in danger because their habitats, or homelands, are disappearing.

Traditional migration paths take birds through countries that are not protecting the places for birds to stop, rest and feed. The scientists studied the migration or flight paths of almost 1,500 species. They decided that 91 percent of them passed through dangerous areas.

The major danger for migratory birds is development. Buildings and pavements have covered the places where birds stop and feed as they move from one part of the world to another. One of the scientists who worked on the study says “Many of these important places have been lost to land reclamation because of urban, industrial and agricultural land expansion”.

The problem, according to scientists, is that many of these small birds die along their migration paths because they don’t have a safe place to feed and rest. There is no place to restore their energy for the next part of their journey. Countries in North Africa, Central Asia and those along the coasts of East Asia are having the most difficult time in protecting land. The scientists say these countries do not have enough areas that are safe for birds. One species that doesn’t exist now is the Eskimo curlew. “Our world gets poorer every time we lose a species,” one of the scientists says.

The researchers say countries need to work together and come up with safe stopping areas for birds that pass through their boundaries. For example, one country might have preserved safe zones for migrating birds. But a neighbor country might not. A bird might die.

One scientist who is not connected with the report tells Los Angeles Times that while some habitats are changing, more work can be done to make urban areas safe for birds.

He says small changes, like planting more native plants or keeping cats out of the areas birds would be likely to use, could make a big difference.