be busy doing sth可以用work on替换吗?如果不能区别是什么?急用!

用be busy doing sth.句型造句 be busy doing sth 例句 be busy in doing sth be busy with sth 与be busy doing sth的区别 ,可以互换吗 he is always busy___ (work)是用be busy doing sth还是 be busy with sth be busy with sth 与be busy doing sth be busy doing sth可以用work on替换吗?如果不能区别是什么?急用! 忙于做某事为什么要用be busy doing sth 可以用be busy to do sth吗为什么不能用to do啊 请用be busy doing sth 的句式造句 英语 翻译 be busy doing sth 有没有be busy with doing sth? BE BUSY DOING STH 是主系表结构吗 be busy doing sth 与be busily doing的区别 be busy doing sth/with sthbe busy doing sth 后跟动词be busy with sth 后跟名词麻烦谁能造个句子 各位帮我整理一些doing sth 的句型比如：be busy doing sth也可以是其他的，比如spend doing sth be busy doing sth和be busy with sth这两个句式的意思和用法 是be busy doing sth还是be busy to do sth? be busy with sth 与be busy doing sth的区别