In many places the weather changes during the year. These changes are called seasons. In the north and south there are four seasons in a year. At the North and South Pole, there are only two seasons. In tropical（热带）places near the Earths equator（赤道）, there are two seasons a wet season and a dry season. Each season brings changes. They are important for plants and animals that live in different parts of the world.

Spring starts when the day and night are the same length. The weather gets warmer and sunnier. Trees and plants start to grow. Many animals have their babies in spring.

Summer begins on the longest day of the year. In the north this is on June 21 or 22. Summer is usually the warmest and sunniest time of the year. Fruit grows faster on trees and plants. Young animals grow bigger and stronger.

Autumn starts when the day and night are the same length again. During autumn, the leaves change color and fall down from the trees. Some animals collect food before winter comes.

Winter begins on the shortest day of the year. In the north this is on December 21 or 22.The weather is colder and in some places there is lots of snow. Plants and trees stop growing. Some animals, like bats and bears, find places to hide and sleep. This is called hibernation.

Many children use the Internet to get useful knowledge(知识) and information, and to relax in their free time. But some of them are not using it in a good way. Here are some rules to make sure you are safe and have fun on the Internet.

◆Make rules for Internet use with your parents. For example, when you can go online, for how long and what activities you can do online.

◆Don't give your password(密码) to anyone else, and never give out the following information: your real name, home address, age, school, phone number or other personal information.

◆Check with your parents before giving out a credit(信用) card number.

◆Never send a photo of yourself to someone in e-mail unless(除非) your parents say it's OK.

◆Check with your parents before going into a chat(聊天) room. Different chat rooms have different rules and attract different kinds of people. You and your parents will want to make sure it's a right place for you.

◆Never agree to meet someone you met on the Internet without your parent's permission(允许). Never meet anyone you met online alone.

◆Always remember that people online may not be who they say they are. Treat (视为)everyone online as if they were strangers.

◆If something you see or read online makes you uncomfortable(不舒服), leave the site. Tell a parent or teacher right away.

◆Treat other people as you'd like to be treated. Never use bad language.

◆Remember—not everything you read on the Internet is true.

I was filled with doubts and worries until my grandfather told me to stand tall.

For me, height was my trouble. I was much taller than other girls, I often bent（ 弯曲） my body at the back of the line. I had always felt unsafe as the tallest student of my class in Bala Cynwyd. And I wasn't looking forward to entering the ninth grade.

My grandfather didn't laugh at me. Instead, whenever I tried to bend myself in order to appear shorter, he would tell me "Stand straight and tall, Alisa. "I trusted my grandfather more than anyone else in my childhood.   And whenever I was afraid of something,   he always told me stories of his life.

My grandfather grew up in war﹣torn（战乱的） Europe. " Stand straight, stand tall "meant something else then. After the war, he went to America. He lived a hard life,   "If they could do it， why couldn't I？""Stand straight, stand tall, "he often reminded（提醒） himself. Thanks to the help of a friend, my grandfather got a job. He once told me that he was very nervous at first． He was not only trying to learn this hard new job but also a new language.

"Stand straight, stand tall, " he would always tell himself. I am so proud of my grandfather. After listening to my grandfather’s unusual experiences, I have changed the way I look at my own life.

"Stand straight, stand tall" has become not only a piece of advice to improve my posture（身姿）.   It also tells me to be proud of who I am.

And I do.

David Silk has always admired people who help others. He admires how they help people. When David was 7 years old, he told his parents, “I want to dress up like a superhero and help the homeless.” A few months later, David’s family planned a day of giving. Wearing his red superhero clothes, David’s happily helped hand out 70 bags of lunches to hungry people in a park in Detroit, Michigan. That’s how Super David was born.

Word spread about David’s good deeds. People donated money and something else, and David handed them out to those in need. When someone donated bottles of water. David and his family drove the car to take the water to Flint, Michigan, a city that had unsafe drinking water. Another time, a shop donated six turkeys to David for Thanksgiving. With his parents’ help, David used social media to ask for more turkeys. “In the end.” he said. “we handed out 64 turkey dinners to families all around Detroit.”

David has a motto(座右铭): Everyone can be a superhero to someone. At an event called the Hero Round Table, David told the listeners, “It’s not difficult to help people. You can keep some socks and snacks in your car to help people in need. Every little thing helps. And it can make others happy.”