BE BUSY DOING STH 是主系表结构吗

be busy in doing sth be busy doing sth 例句 be busy doing sth/with sth be busy with sth 与be busy doing sth的区别 ,可以互换吗 be busy with sth 与be busy doing sth be busy doing sth和be busy with sth be busy with sth.be busy doing sth. 英语 翻译 be busy doing sth 用be busy doing sth.句型造句 有没有be busy with doing sth? be busy doing sth等于什么 be busy with sth.spend on sth.be busy doing sth.spend doing