A plant is a living thing. It uses its many parts to grow from a small seed to a large plant. Each part helps the plant stay healthy. Plants also need sunlight to grow. They get light from the sun and minerals from the soil. These things help the plant stay alive and grow. 

    What's a spacewalk? Any time an astronaut gets out of a spacecraft(航天器) while in space, it is called a spacewalk. Astronauts go on spacewalks for many reasons. For example, experiments can be placed on the outside of a spacecraft. This lets scientists learn how being in space affects(影响) different things. By going on spacewalks, astronauts can also fix things instead of bringing them back to the earth to fix.

    When astronauts go on spacewalks, they wear spacesuits to keep themselves safe. Inside spacesuits, astronauts have the oxygen(氧气) they need to breathe and the water they need to drink. To keep the astronauts and the spacecraft safe, the astronauts must leave and go back to the spacecraft through a special door. When on a spacewalk, astronauts use safety  tethers to stay close to their spacecraft. Tethers are like ropes, connect the spacewalkers with the spacecraft. They keep astronauts from floating(漂浮) away into space. Another way astronauts stay safe during spacewalks is by wearing a SAFER. SAFER is worn like a backpack. It helps an astronaut move around in space.

    How do astronauts train for spacewalks? One way is by going for a swim. Floating in space is a lot like floating in water. Astronauts practice spacewalks underwater in a huge special swimming pool. For every one hour they will spend on a spacewalk, astronauts need to train seven hours in the pool. Another way astronauts practice for a spacewalk is by using virtual reality(虚拟现实). It looks and feels just like a spacewalk.

    Today, only three countries have finished spacewalks independently. They are Russia, the United States and China. The first person to go on a spacewalk in the world was Alexei Leonov from Russia. Zhai Zhigang is the first Chinese astronaut to go on a spacewalk. The world record of spacewalks is held by Russian astronaut Anatoly Solovyev. He has been on 16 spacewalks and spent more than 82 hours outside in space.

Every school has its own rules.The rules change from one school to another.There are also some rules that look strange or funny to us.Here are some funny school rules.

Japan：Most schools demand（要求） that students wear uniforms，such as sports suits or skirts.They also demand that girls' white socks should be folded（折叠）（某种） way and boys' heads should be shared（剃）.

The US：At some US schools，students must have a pair of indoor shoes to change into every day.Chewing gum（口香糖） is not allowed（允许），because it is difficult to clean up.

Britain：Strange hairstyles（奇怪的发型）are not allowed at some British schools.But they might（可能）allow students to wear certain hairstyles during the World Cup.

Many people in the world are short of basic skills. That's why governments are paying attention to food education（教育） in schools. They want students to have a good relationship (关系) with food and know about its importance. 

Schools give kids different information on food. So, students learn about not only healthy eating but also food production (生产) . They learn to make different food, too. 

For example, UK students from 7 to 14 must learn to cook simple meals. In this way, students can learn a useful skill and good food habits. 

In the US, schools use a farm-to-school way. They buy fresh food from local farms for their restaurants. Students also go on field trips to the farms. In some areas, US students learn to garden, too. When they grow their own fruit and vegetables, they respect food more. They also try not to waste(浪费）it. 

Japan even has a rule on food education. Students can't miss breakfast, and they can't eat fast food. Students are living healthier lives because of good food education.