I'm doing homework.

我正在做功课。

youdao

I'm just doing my homework.

我只是在做我的家庭作业。

youdao

I have to sit at desk and do my homework, which can not be finished until midnight, I'm tired of doing much homework, get bored at taking so many exams, and lose interest in studying.

我不得不坐在桌前做作业，作业直到午夜才能做完。我讨厌这么多的作业和如此多的考试，对学习失去了兴趣。

youdao

Sometimes when I'm doing my homework, I just get carried away with talking to my friends online but my mum comes and tells me when it's time to stop.

BBC: Teenagers and their sleepless lives