CECF

例句：

1. 1.This is the correct answer to your question.
   这是你问题的正确答案。
2. 2. The teacher gave us a lesson on chemistry today.
   老师今天给我们上了一堂化学课。
3. 3. She has been working in this field for over ten years.
   她在这个领域工作了十年以上。