In some science fiction movies, evil robots refuse to die, no matter how hard people fight back.

    Now science fiction has become science fact. For the first time, scientists have made a robot that can take a beating (挨打) and keep on going. Scientists from Cornell University made the robot, which looks like a spider with four legs.

    Until now, even the most advanced (先进的) robot was almost certain to break down when it was damaged. That is because its computer inside simply doesn't know how to make the machine work after its shape has changed.

    To deal with this problem, the scientists put eight motors (发动机) and two sensors (传感器) that read how the machine is working. They all give signals to the machine's software. Using this information, the computer can then figure out the machine's shape at any moment.

    The new technology is a big advance in robot-making, scientists say, and it's far from scary. It may someday help scientists create better artificial (假的) arms and legs and give new freedom to people who lose them. It might also help scientists understand how people and animals figure out their own sense of place in space.

    “It has been difficult to design robots that can work well when the environment changes or when it's damaged,” says Olaf Sporns of Indiana University in US. “With this work, we are nearer to solving this problem.”

    In northern China during spring, big sandstorms often make trouble for people. When the sky is dark with sand, buses and cars all move much more slowly. Sometimes, people can't even see for 20 metres.

    Sandstorms usually happen in spring. Big sandstorms happened in more than 10 provinces in northern China last year. More than 70 million people have had problems in those places because of the sandstorms.

    People in southern China don't have to worry about this kind of bad weather. Most of the sand comes from the north of China. In northern China, lots of places have few trees and don't get much rain. People there have been cutting down too many trees. When there aren't many trees, the ground can't keep enough water. Over the years, the ground dries up and turns to sand. When spring comes and the ice melts (融化), the ground becomes looser (更松散的). Strong winds take the loose sand into the sky.

    Sandstorms are bad for people's health. If people take in too much sand, they could cough or have asthma (哮喘).

    Sandstorms also give farmers lots of problems. Sometimes their sheep get lost in the storms and never get back home. The winds also tear down farmers' houses.

    What can you do to stop sandstorms? Here's an idea: Ask your parents to help you plant some trees this spring.

    If you see people cutting down too many trees, tell them about the dangers of sandstorms, and ask your government to stop them from cutting.

Walking around the city, you will see girls wearing hanfu on the underground or people wearing T-shirt with Chinese characters in the streets. 

This situation is becoming more and more common in China. It's guochao or China-Chic. Guochao adds traditional Chinese culture {#blank#}1{#/blank#} products, and it shows the rise of China's local brands. 

Before 2018, famous foreign companies p{#blank#}2{#/blank#} a main role in the world market. There were few Chinese brands. In 2018, Chinese sportswear brand Li Ning made changes to the situation. It introduced its Wu Dao collection to the world. The collection not only looked cool, but also i{#blank#}3{#/blank#} elements (元素) of traditional Chinese culture. It quickly {#blank#}4{#/blank#}(catch) people's eyes at home and abroad. And it created a{#blank#}5{#/blank#} sales. 

Soon, Chinese local brands became more and more popular all over China. For example, White Rabbit, whose sweet candies bring back childhood m{#blank#}6{#/blank#}for many people, began to sell other products, like milk tea and ice-cream. By doing so, it w{#blank#}7{#/blank#} the heart of young people. 

These brands got what they wanted. Young people gradually turned their attention from western culture to guochao. Some of them are {#blank#}8{#/blank#} (work) together to spread Chinese culture to people around the world. 

According to a survey, 68% Chinese people prefer Chinese brands. Among them, 62% say they are o{#blank#}9{#/blank#}to international brands, but local brands remain the first {#blank#}10{#/blank#} (choose). 

No matter how guochao develops, there is one, thing that won't change-people are, becoming more and more confident about our country's development and culture. 

If you've ever used pi in math class, you probably used the number 3.14. In fact, the number for pi is much longer. Pi is called an irrational number (无理数) because the digits (数位) after the decimal point (小数点) never end or repeat.

In 2015, a young man from India named Rajveer Meena set a world record by memorizing 70,000 digits of pi. But pi is much longer than that.

On Pi Day ( March 14th) this year, a company called Solidigm said it calculated (计算) pi to105 trillion (万亿) digits. And the 105 trillionth digit is 6. It broke the record for how many digits of pi we know.

Pi is really useful for circles in math. It helps us connect the circumference with the diameter of a circle.

Even NASA scientists use pi for their work of studying space. But they only need about 15 digits of pi for their calculations.

Calculating pi also has another important use. It's how scientists test new computer programs and data storage systems (数据存储系统).

Solidigm's calculation of pi took around 75 days to finish. The company's owner Brian Beeler said that the achievement needed a lot of work. They had to plan the calculation very carefully.

This isn't the first time that Solidigm has calculated pi. In 2022, Google Cloud calculated 100 trillion digits of pi. Solidigm matched that in 2023.

In the future, we'll keep finding more and more digits of pi. We'll never be able to calculate all the digits of pi because it goes on forever. But it still helps us see how great computers can be.

Many sports stars believe something can bring them good luck. Some of them like to wear their lucky clothes, some like special numbers and some do special things for good luck on the day of an important game. Next I'll give you some examples.

Serena Williams, a tennis player, ties her shoelaces(鞋带) in the same way before every game. She usually wears the same socks in all games. She also has lucky shoes and likes having a dress with her. Another tennis star, Rafael Nadal, puts two water bottles in the same place next to the tennis field before every game. When he wins a competition, he always bites the trophy(咬奖杯).

The Spanish football player, Fernando Torres, always has three shirts, three pairs of shorts and three pairs of shoes in his sports bag. Kolo Touré is always the last player going onto the football field before games. He believes that numbers like 11,22 or 33 on a player's shirt can bring the player good luck. He also thinks it is unlucky to change the numbers when he goes to another team.

One racing driver. Sebastian Vettel, doesn't have a special thing to do but he has lucky things. He has a necklace (项链) and a little toy pigl They are surely special to him.

Birthdays are celebrated all over the world. Some traditions are rather similar from one country to another：candles, cakes and birthday wishes. But there are also different ways to celebrate birthdays. Here are a few：

Argentina（阿根廷）：In Argentina, as in many Latin American countries, one of the most important birthday parties is a girl's fifteenth. When girls turn 15, they have a huge party and dance first with their fathers, and then the boys at the party.China：The birthday child receives presents from the parents. Friends and family members are invited to dinner, and noodles are served to wish the birthday child a long life.

Denmark（丹麦）：A flag is flown outside a window to show that someone who lives in that house is celebrating the birthday. Presents are placed around the child's bed while he is sleeping so he can see them immediately when he wakes up.

Holland（荷兰）：The birthday child receives an especially large present. The family also put flowers or balloons on the birthday child's chair to make it beautiful.India：Usually Indian children wear white to school. However, the birthday child wears colored clothes to school and gives out chocolates to everyone in the class. His/Her best friend helps do this.

Japan：The birthday child wears new clothes to mark the special time. Certain birthdays are more important than others and these are celebrated with a visit to the shrine（神殿）. These are the third and seventh birthdays for girls and the fifth for boys.