忙于

máng yú chǎo gǔ

忙于炒股

be busy trading in stocks

máng yú pī kǎo juàn

忙于批考卷

be up to one's eyebrows in marking exam papers

tā zhèng zài máng yú wèi tā de xiǎo shuō shōu jí zī liào

他正在忙于为他的小说收集资料。

He is on the wing gathering material for his novels.

tā zhěng tiān dōu máng yú jiā wù

她整天都忙于家务。

She is busy with housework the whole day.

máng yú gōng zuò

忙于工作

be busy at work

tā máng yú chuàng jiàn zì jǐ de shì yè

他忙于创建自己的事业。

He’s been busy building his career.

tā máng yú gōng kè

他忙于功课。

He was busy with his homework.