be busy at和别的介词的区别

确实有 be busy at... ...

忙于做某事：be busy at (with，about，over，doing) sth 都可以。

如：妈妈整天忙于做家务。可以说：My mum is busy at housework all day.

这个句子中at可以用括号里的词替换

be busy in doing sth（正忙于做某事），一般将in省略了，就写成be busy doing sth了

没见过be busy on或者at的，只有be busy with sth，意思和be busy in doing sth一样，如：

1、be busy with sth

例如:I am busy with my homework!

2、be busy in doing sth

例如:I am busy in doing my homework