他忙于集郵。
They are occupying themselves in growing their own food.

他們自己正忙于種植自己所需的糧食。
Haas occupied himself in writing his research paper.

哈斯忙于寫他的調查報告。
Jacelin occupied himself with solving some geometry problems.

杰斯林專心于解決一些幾何問題。
Some occupied themselves with studying English.

有幾個人在學英語。
He has been deeply occupied in listening to a tape.

他一直在忙于專心聽錄音。
He was occupied in writing letters.

他忙于寫信。
Many people in this area are occupied with agriculture.

這一地區許多人從事農業。
Some students were occupied with reviewing their lessons.

有幾個學生在復習功課。