be engaged in ...

• 从事于 ...； 忙于 ...

be engaged in ...的用法和样例：

例句

1. He was engaged in medical research.
   他从事于医学的研究。
2. I am happy to engage in espress industry.
   我很乐意从事于快递这一行。
3. We are engaged in writing a letter.
   我们正忙于写信。
4. He was employed in watering the garden.
   他忙于给花园里的花木浇水。