calycanthemy

例句：

1. 1.The chalkboard is covered with a layer of dust and grime.
   黑板上覆盖着一层灰尘和污垢。
2. 2.The teacher asked the students to clean the classroom before the next class.
   老师要求学生们在下一节课前打扫教室。
3. 3. The old man was sitting on the bench, watching the children playing in the park.
   老人坐在长椅上，看着孩子们在公园里玩耍。