He is busy doing his homework.

他忙于做作业。

She is busy doing the cooking.

她忙于做晚餐。

The kids are busy doing crafts.

孩子们忙于做手工艺品。

We are busy doing the project report.

我们忙于做项目报告。

They are busy doing the preparations.

他们忙于做准备工作。

Be busy doing sth be busy with sth

忙于……忙于做什么事忙于

Be busy doing give up doing

放弃做某事忙于做某事

A be busy doing sth.

意为“忙于做某事”。故选A。

He is busy doing housework.

他忙于做家务.

You are not busy doing anything, are you?

医生正在忙着给病人做手术。