The 500-word explanatory text of turtle is as follows:

First of all, turtle is a reptile that usually lives in water or on land. Their bodies are flat and have a hard shell covered with cuticles that protect them from external damage. Turtles' heads, limbs, and tails are all retracted into their shells. When threatened, they will quickly retract their bodies into their shells to protect themselves. The turtle's shell is divided into two halves, and each side is divided into many small grids. Each grid has a special name, such as ingot grid, spiral pattern, etc.

Secondly, the living habits of turtles are also very interesting. They are nocturnal animals and tend to hide in their shells or in the mud at the bottom of the water during the day to avoid threats from natural predators. At night, they come out to feed and play. In addition, turtles are also cold-blooded animals and will adjust their body temperature as the temperature changes. When the water temperature is too high or too low, they will choose to change the water or hide back in their shells to rest.

Historically, the image of the turtle has appeared in many cultures. In ancient civilizations, the turtle was considered a symbol of good luck, as it represented longevity and prosperity. In traditional Chinese culture, the image of turtle is widely used in art, religion and politics. At the same time, in the ancient Egyptian civilization, people believed that the turtle was one of the longest-lived animals and regarded it as a symbol of mystery and sacredness.

In addition, turtles also have a profound impact on human society. In addition to their popularity as ornamental animals, turtles are also widely used in science and medicine. Turtle shells are used as medicine and ornaments, and are said to have healing properties for wounds and diseases. In addition, the patterns on turtle shells are also widely used in jewelry and works of art.

Finally, let’s summarize the introduction to the characteristics and living habits of turtles. Turtles are popular animals that fascinate people for their hard shells and long lifespans. Although turtles will take emergency measures to shrink their shells when threatened, this animal is actually very friendly and deserves our attention and understanding. By learning about the living habits and cultural background of turtles, we can better understand this ancient and magical animal.

The role of expository writing

1. Convey information: The main goal of expository writing is to convey information so that readers can understand a specific topic or concept. This can be a variety of topics from science to everyday life, such as the nutritional content of food, how computers work, or how to make a cake.

2. Education: The main purpose of expository writing is to educate readers and help them understand new or complex concepts. By providing clear, accurate information, expository writing can help readers expand their knowledge base and improve their understanding.

3. Explanation and illustration: The goal of expository writing is to explain and illustrate complex concepts or processes. This might involve explaining complex scientific principles or detailing a process. By using clear explanations and specific examples, expository writing can help readers better understand these concepts or processes.

4. Inspire thinking: Although the main goal of expository texts is to convey information, they can also inspire readers to think. By providing new ideas or information, expository writing can spark readers' curiosity and lead them to further exploration and research.

5. Exchange and communication: Expository writing is an important tool for people to communicate and communicate. They can help people share information, share knowledge, or explain complex topics or concepts to those who are unfamiliar with them.

6. Practicality and guidance: Due to the practicality and guidance of expository texts, they play an important role in many fields, including education, science, technology, medicine, etc. They provide readers with accurate and detailed information on a specific topic to help them make decisions or take action.

7. Trust and reliability: In many cases, the accuracy and reliability of expository writing can provide organizations or individuals with a guarantee of trust and reliability. When people trust the information they are reading, they are more likely to accept and follow advice or guidance.

8. Improve knowledge level: By reading expository texts, readers can improve their knowledge level, expand their horizons, and enhance their understanding of new topics. This not only increases their knowledge but also improves their critical thinking and problem-solving skills.

9. Promote understanding and acceptance: In some cases, expository writing can help promote understanding and acceptance of new topics.

For example, when a new concept is difficult for a group to understand, expository writing can help them better understand and accept the concept by providing detailed explanations and clear steps.