【推荐1】I don’t like circuses (马戏团) that use animals.     1     Circuses are not the right places for lions, tigers or elephants. They should not be kept in cages   (笼子).     2     They need to stay close to their families. They should not be made to do tricks (戏法). They should live in the wild.

Some people think that it’s all right to use animals such as horses in circuses. I disagree with them on that.     3     The horses wouldn’t like being driven around in a truck for hours and hours, unable to get fresh air.

I don’t think circuses should use any animals at all. Circuses should have only human actors.     4     Human circuses are lots of fun. I love these kinds of circuses.

Most animal circuses are cruel (残忍的). Some countries don’t let circuses use lions, tigers or elephants.     5     I only hope that in the coming years all the countries in the world will stop using animals in their circuses.

【推荐3】A safe new home

The large female wolf ran, and the six wolves in the group followed. She heard the whirr (呼呼声), whirr of a huge bird and saw its shadow on the snow. She was trying to lead the group to the safety of the trees across the field.

Soon the wolf could not run anymore, and she fell to the ground. She did not know about the dart (箭；镖) in her side. It was filled with medicine to make her sleep. When the wolf awoke, she was puzzled by the strange sound and the darkness.             

Suddenly, she saw another wolf. It was her grown daughter! The two wolves greeted each other by licking (舔) and rubbing.        

For a long time, the two wolves lay curled together in this dark place. The ground was rocking back and forth under them. The rocking motion stopped and suddenly sunlight appeared. Two strange creatures were standing before them. The wolves had never seen people before. The large wolf showed her teeth and shouted at them.

For a short time the two wolves lived inside an area with railings (圈栏) around. Meat was brought for them to eat, and they had each other for company. From the inside the wolves saw trees and snow, and they smelt the air. Soon they got used to this new place.                 

One spring day the strangers arrived to open the gate. The large wolf carefully went near the opening and then rushed out. She called, and her daughter followed. They ran like the wind. They were free!

“May they have long and happy lives here in Yellowstone National Park!” said the hopefulr voice of the park keeper!

【推荐2】Researchers found how parents’ communication styles help their young children to develop language skills. Daniel Yurovsky, professor in psychology at Carnegie Mellon University and his team developed a method to experimentally evaluate how parents use what they know about their children’s language when they talk to them.They found that parents have extremely exact models of their children’s language knowledge, and use these models to tune (调正) the language they use when speaking to them.

“We have known for years that parents talk to children more differently than to other adults in a lot of ways. For example, simplifying their speech, repeating words and stretching out vowel sounds.” said Yurovsky. “That helps young kids get a toehold into language, but whether parents change the way they talk as children are learning language, gives children language input that is ‘just right’ for learning the next thing.”

Yurovsky and his team continued to study to understand exactly how parents tune their interactions to match their child’s speech development. The team developed a game where parents helped their children to pick a specific animal from a set of three. Half of the animals in the matching game were animals that children typically learn before age 2, like cat and cow. And the other half were animals that are typically learned later such as peacock and leopard. The researchers asked 41 child-adult pairs to play the game. They measured the differences in how parents talked about animals they thought their children knew and those they thought their children did not know.

They found parents had an unbelievable exact knowledge of their child’s language because they had watched them grow and learn. These results showed that parents leveraged (利用) their knowledge of their children’s language development to fine-tune the information they provided.

“We found that parents not only used what they already knew about their children’s language knowledge before the study, but also that if they found out they were wrong—their child didn’t actually know ‘leopard’, for example, they changed the way they talked about that animal the next time around.” said Yurovsky. “Right now we train language models by giving them all of the language data we can get our hands on all at once. But we might do better if we could give them the right data at the right time, keeping it at just the right level that they are ready for.” Yurovsky added.

【推荐3】Scientists have discovered what they believe is the world’s largest plant, an underwater field of sea grass that spreads for 180 kilometers in Shark Bay, off the west coast of Australia.

Sea grasses are flowering plants that grow in shallow (浅的) waters near coasts. They grow together in thick fields, known as meadows (草地), helping clean the ocean’s water. They also provide food and shelter for many sea lives. The huge sea grass meadow in Shark Bay is a kind of sea grass called Posidonia australis and it has spread widely all through Shark Bay.

Scientists wanted to study the sea grass, so they took samples (样本) from 10 different parts of this huge meadow.

Many plants create new plants by growing flowers and spreading seeds (种子). The DNA of the plants that grow from these seeds is a little different from the DNA of the plants that the seeds came from. By comparing the DNA from their samples, the scientists hoped to get an idea of how many different sea grass plants there were in the meadow.

What they learned made them astonished—all of the grass samples had almost exactly the same DNA. That meant that they were all just one plant. One big sea grass plant spreads out over 200 square kilometers. This makes it the largest known plant in the world, by far.

So how has the Shark Bay sea grass grown so large? Instead of spreading with flowers and seeds, it spreads by copying or cloning (克隆) itself. It generally grows and spreads about 35 centimeters a year. Because of the history of Shark Bay and the speed of growth, the scientists believe that the plant is about 4,500 years old.

The sea grass in Shark Bay is also unusual in another way. It’s a “polyploid” (多倍体). Usually, an organism (有机体) has two parents, and gets half of its DNA from each. But polyploid organisms have all of the DNA from both parents, meaning they have twice as much DNA. The researchers believe this may play a part in the success of the sea grass.

【推荐1】

China welcomed three heroic astronauts home on April 16. The re-entry module (返回舱) carrying Zhai Zhigang, Wang Yaping and Ye Guangfu touched down safely at the designated (指定的) Dongfeng Landing Site in Inner Mongolia autonomous region. This ended the Shenzhou XIII astronauts’ six-month space mission.

This return marks a major breakthrough for China’s efforts in space. Let’s look at some of the technical details of the mission.

The mission set a new speed record. The Shenzhou XII return capsule revolved around the Earth 11 times over 24 hours, before returning on Sept 17, 2021. This time Shenzhou XIII shortened the time to about 9 hours, orbiting the Earth five times.

The Shenzhou XIII mission was simplified to only five orbits and was designed to return more efficiently.

This approach required more precise control of the spacecraft and more accurate orbital calculations. This meant that when the spacecraft separated, it could quickly target the landing area, calculate the return path, and adjust its altitude. Having the ability to adopt such a fast return method indicates that China’s return technology for manned missions is very mature and reliable.

Another challenge for astronauts returning to Earth is traveling through the atmosphere. After the re-entry capsule enters the atmosphere, there is fierce friction (摩擦) with the air. The surface temperature of the capsule can reach thousands of degrees.

To solve this problem, the researchers designed a heat-resistant coating on the surface of the Shenzhou XIII return capsule. They also laid a layer of ablative material (烧蚀材料) that sublimated (升华) and fell off when the temperature reached a certain level, taking a lot of heat with it.

The re-entry capsule landed upright (直立的) in the designated area. Such a landing position is rare in China’s space flight history. So far, only Shenzhou VI and Shenzhou XIII have achieved an upright landing. To achieve this, astronauts must operate and let go of parachute (降落伞) with precise timing. A small mistake may cause the capsule to be pulled down by the parachute. Landing upright is the ideal way to land, ensuring astronauts have the softest landing.