As an AI language model, I can provide you with a sample essay that you can use as a reference for your English CET-4 exam. Here is an example:

Topic: The Importance of Learning a Foreign Language

Learning a foreign language is becoming increasingly important in today's globalized world. The ability to speak and understand another language can help us communicate with people from different countries and cultures. It can also open up new opportunities for personal and professional growth.

Firstly, learning a foreign language can enhance our cultural awareness and understanding. When we learn a language, we also learn about the culture and history of the people who speak it. This can broaden our horizons and help us appreciate different perspectives. For example, by learning Chinese, we can gain a deeper understanding of the rich cultural heritage of China and develop a greater appreciation for its art, literature, and philosophy.

Secondly, proficiency in a foreign language can improve our job prospects and career opportunities. Many companies now operate on a global scale and require employees who can communicate effectively with clients and colleagues from different countries. By being able to speak another language, we can demonstrate our ability to work in a multicultural environment and make ourselves more valuable to employers.

Finally, learning a foreign language can also benefit our mental abilities. Studies have shown that learning a new language can improve cognitive functions such as memory, problem-solving, and concentration. It can also delay the onset of age-related cognitive decline and dementia.

In conclusion, learning a foreign language is an essential skill in today's interconnected world. It can broaden our cultural horizons, enhance our job prospects, and improve our mental abilities. Therefore, we should make an effort to learn at least one foreign language and embrace the opportunities it brings.