be busy at和别的介词的区别
问题描述：
be busy at和别的介词的区别
老师说有be busy at.
答
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.