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He asked the soldiers to line up in rows (排，行) of 3. When they did, 2 soldiers were left. Then he told them to line up in rows of 5, and this time 3 soldiers were left. Finally, he made them line up in rows of 7, and 2 soldiers were left.

Han Xin thought for a moment and said, "We have 233 soldiers". Everyone was surprised. How did he know that so quickly?

Han Xin used a special maths method wisely. He just looked for a number that fits three simple rules: when you make groups of 3, 2 are left; make groups of 5, 3 are left; make groups of 7, 2 are left. The smallest number that works is 23. But his army was much bigger. He knew that if he added 105 (which is 3×5×7) to 23, the new number would still fit the rules. Adding 105 twice to 23 gives 23+105+105=233, which was just right for his army size.

This story shows that maths can solve problems in clever ways. Even today, this kind of maths called "remainder problems" (盈亏问题), is still used in many fields. Ancient stories teach us useful maths skills. How great they are!

As one of China's most famous mountains, Mount Tai welcomes over 8 million tourists every year. With such a large number of visitors, lots of rubbish is created every day, and transporting this large amount of waste has always been a big problem. That's why the robot dog has been brought in.

We believe the best ways to solve the problem are drone transport (无人机运输) and robot dog transport, according to a worker from the Taishan Cultural Tourism Group's property (房地产) company. The company has worked with a few technology companies and they have finally chosen Unitree Robotics to do rubbish transport tests.

Jin Da, a manager at Unitree Robotics, said that the robot dog, Unitree B2, is very good at walking on stairs. And it can keep balance even on wet or difficult ground when climbing the mountain. It can also easily get over things like piles of wood and steps as high as 40 cm. Besides, the robot dog has a battery life of four to six hours, and it can carry a weight of 120 kg.

After three days of testing, the robot dog could get used to 80% of the road conditions (状况) on Mount Tai. The successful climb shows how reliable and useful it is in difficult conditions. And this also provides important experience and data for future uses, such as rescue work, exploration, transport, and other areas. "We are still testing the robot dog, and we will further improve the design to start the next round of testing as soon as possible," Jin said.

Wei Dongyi was born in Shandong in 1991. Growing up, he lived in a world full of numbers. His father, a maths teacher, often shared interesting maths stories with him. One day, when he was a young boy, he read a special book about maths. From that moment on, he showed great interest in maths. He would sit at his desk for hours, trying to solve the most difficult problems, and he never felt bored.

When Wei was in middle school, he joined the school's maths team. Even though he was younger than many team members, hestood out quickly. Once, his classmates spent days on a hard maths problem. But Wei found a clever way to solve it in just a few minutes. His teachers were so excited that they called his solution the "Wei's Method".

At the age of 16, Wei took part in the International Mathematical Olympiad (IMO), a very famous and difficult maths competition. He faced six tough problems, but he solved them all perfectly and got full marks. What's more, he did it again the next year. Because of his excellent performance, he entered Peking University without the college entrance exam.

Now, as a teacher at Peking University, Wei still loves maths more than anything else. He spends his days studying new maths ideas and helping students. His story teaches us that with love and hard work, we can all become wizards in our own ways.

In ancient times when a man wanted to tell how many animals he3, he had no system of numbers to use. He had to put a4 into a bag for each animal. The more animals he owned, the more stones he had. In this way, the ancient people knew the number of the animals. It may explain5 the word "calculate" comes from the Latin word "calculus." "Calculus" means "stone".

Then, human beings used lines to count. People would just draw a line for each thing they wanted to count, but they still had no6 to tell the numbers. There was not any symbol they could use to express the number, so they could not write the numbers down.

Later on, people used fingers. Again, we have the word that goes back to this. The word "digit"7 the Latin word "digitus". It means "finger". Everyone has 10 fingers so it8 the use of 10 in the system of numbers. This system of numbers was created by Indian mathematicians. They9 the numbers we use today. Later, the Arab traders10 it to Europe during the 9th century and made it used wisely. In this way, people count things with ten numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9 and 0. It is called decimal system. That is to say, it is built on the base of 10.

Ted took out his tools and began to work. After4 busy in the kitchen for one afternoon, he created a new invention. He took a broken wood mixer (搅拌器) apart and then connected a motor (电动机) to the wooden stick. When he turned it on, it was able to stir things by itself5 it got power from the motor. It was so convenient that anyone6 stir the sauce easily and quickly.

The next day, Ted showed his7 to his mother. She was surprised and allowed him8 more time improving it. He tried, failed and then tried again. Finally, he added9 new. He made a timer so that the user could leave the tool on the table without being worried about burning the sauce.

Ted's invention turned out to be as10 as mum's old mixer.11 mum's support, Ted decided to bring it to school and introduce it to his eight12 schoolmates. Suddenly, Ted's invention became a big hit in his school. They used it to mix drinks or stir13 kind of sauce at lunch, and it was also easy to clean and store. When his friends used the invention, Ted watched them14 to see if there were any problems. In School Science Festival, Ted even received15 prize from the school for his creativity and intelligence.

Perhaps not everyone can be an inventor. However, it is always meaningful to find out what you are really interested in and keep going like Ted.

注意：

1.词数70左右（文章开头已给出，不计入词数，请根据要点提示适当发挥）。

2.不得透露学校、姓名等任何个人信息，否则不予评分。

参考词汇："永不放弃的人"："The Man Who Never Gave Up"。

Thomas Edison was a very famous American inventor.

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the animal world is!

These skills in their survival.

bird, like the parrot, can even small numbers!

We should protect animals ignoring them. Otherwise, they may .

This ability how humans use numbers.

Elephants can remember , like food and water.

Some animals learn to remember information in their minds .

Numbers are very important to us, and we see them every day. Last week, our math teacher asked us to c the money for our class party budget. Everyone took out their n and wrote down each expense clearly: 20 yuan for snacks, 15 yuan for drinks, and 10 yuan for decorations. After finishing, we c our results together. I made a small mistake at first, but Lucy is a t girl—she is good at using numbers. Her answer was e right: the total was 45 yuan! All of us in the class agreed that numbers help us avoid mistakes. We also use numbers e, such as airports, supermarkets. Without numbers, life would be messy. So let's learn to use numbers well. They are our helpful friends!

One big problem is wildfires. For example, because of the hot, dry weather, big fires burned in 2020 and 2021. It may take much longer for both humans and nature to recover (恢复).

These beetles lived peacefully with sequoias in the past, but now they're attacking them. They dig holes in the highest parts of the tree. The beetles are small, but there are so many of them that they can kill a giant tree in just six months!

Scientists are trying to help. However, it is impossible to climb every tree and look at its highest part. So now, scientists are using robots and satellites to record beetle activity over large areas of forest. In this way, they can help protect more trees.

A. Sadly, about 20% of the world's 75,000 sequoias were killed.

B. And slowly these insects move down the trunk, eating the tree as they go.

C. Another problem comes from bark beetles, the tiny insects.

D. But they are in trouble.

E. They climb the trees to look for beetle holes.

Almost all animals need to sleep to stay healthy. But sleeping can be dangerous because other animals may hunt sleeping animals. To help them stay safe, animals have many different ways of sleeping. Some of these ways may surprise you!

Some seabirds can sleep while they fly. These large birds spend most of their lives over the ocean. They are in danger on the water, but they are safe in the air. They glide (滑行) for many hours without moving their wings up and down. Sometimes they sleep while they glide.

A dolphin sleeps with just half its brain at a time. It must stay awake to breathe and to watch for danger. Dolphins can swim without sleep for two months to stay safe. Ducks sleep with just half their brains, too. These ducks often sleep in a line. The ducks at both ends help keep the group safe. They keep one eye open to watch for danger. The ducks in the middle sleep with both eyes closed.

Seals breathe air, but that doesn't stop them from sleeping underwater. They hold their breath and dive deep to sleep for up to twenty minutes at a time. Some fish make their own sleeping bags. They make a big bubble and sleep inside it. It also keeps other animals from smelling them. If an animal hits the bubble, the fish swims away quickly.

Hello! I'm Li Bing, an ancient engineer from Qin State. Let me tell you about Dujiangyan—the world's oldest working water system. We built it over 2,200 years ago!

What was our problem?

Long ago, people in Sichuan faced a big problem. In rainy seasons, the Min River often flooded their farms. But in dry seasons, there was no water for crops.

How did we solve it?

Instead of building dam walls to block the water, we let the water run its own way.

First, my team had to cut through Mount Yulei to make the Baopingkou (宝瓶口). It led part of the Min River to run east. Without any machines, we could only use fire and freezing water to break the rocks open. This took us eight years. Then we built the Yuzui (鱼嘴) to divide the river into two parts. One part carried water to farms, while the other stopped floods. The next problem was the sand and stones in the Min River. We built Feishayan (飞沙堰) to wash them away with water power and keep the system clean.

Why can it last so long?

It is our smart design. We made the deeper Inner River and the lower Feishayan, so the system could control the water during the flood and dry seasons. And for over 1,000 years, workers clean and take care of it every year.

What does it bring?

This is our greatest contribution: A river system grew. It not only made the land around Chengdu rich, but also waters over 7,700 square kilometers of farmland, and feeds 30 million people in 8 cities today. Besides, it is now a UNESCO World Heritage Site. To remember my son and me, locals celebrated with a traditional festival every spring. Also, Erwang Temple was built to honour us.

What is the key to building it?

Actually, we just listened to the water and followed its nature.

The next morning, Lily found a small notebook on her desk. Inside were colorful drawings: a maths problem turned into a friendly monster saying "Solve me!" Next to it was a step-by-step guide written in her dad's lovely handwriting.

For two weeks, her parents worked secretly without telling her. After dinner, her mom would draw funny characters for each maths concept or idea while her dad searched online for easy explanations. They filled the notebook with funny sentences too. "Why is six afraid of seven? Because seven ate nine!..." Words like these made Lily laugh even during practice.

On the test day, Lily felt nervous until she remembered the notebook's smiling sun drawing. When she saw a difficult question, her dad's notes appeared in her mind, "Break it into small steps." She passed the test with a B!

That evening, Lily opened the notebook again. This time, she found a new page. Her mom had drawn a big heart with the words, "We knew you could do it. You're always our smart girl!"

Lily hugged the notebook close and smiled. It wasn't just a study guide—it was her parents' love that helped her through difficulties.

Early in September, I planned to run for the monitor in the class election. I enjoyed speaking in front of many people and was always friendly to others, so I thought it was1 for me to win.

I kept preparing in the following2, thinking about everything for my election. I put up my posters in the classroom. I also spent hours on my3, saying that when anyone of my classmates had a(n)4, he/she could always ask me for help. I felt quite sure about my winning because I prepared it5.

But when I gave my long talk on Election Day in late September, it wasn't what I imagined. Things were6. During my talk, most of my classmates were not listening. They were just doing their homework. But when it was time for another classmate, everyone7 his name and cheered. His talk was much8 than mine, but with a lot of helpful ideas. Soon he finished his talk. At that moment, I knew I was out.

The next day, at school, I just didn't want to hear it while my class were still talking about the election. Later things got better. People9 about the election and talked to me just as they did before.

I didn't win, but I wasn't10 putting so much time and energy into the election. I have learned a lot. Things aren't always going the way we want. We should learn to face these moments and work harder to make ourselves better!