为什么用be busy doing而不是be busy to do我觉得这个用法应该是be adj.to do 比如说be easy to do 为什么这个是be busy doing

为什么用be busy doing而不是be busy to do我觉得这个用法应该是be adj.to do 比如说be easy to do 为什么这个是be busy doing 为什么是be busy doing而不是be busy to do 用be busy doing sth.句型造句 be busy doing造句 be+busy+doing=be+( )+( be busy doing 和 be busy in doing 的区别? be busy with doing 与be busy doing 区别 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 be busy doing等于什么 be busy doing sth 例句 be busy in doing sth be busy doing 过去式+造句 “使忙于”用英语怎么说?要动词,别说be busy doing be busy with he is always busy___ (work)是用be busy doing sth还是 be busy with sth Last Saturday I was busy ( ) my homework .为什么答案是with 而不是doing 请用be busy doing sth 的句式造句 jean is busy cooking in the kitchen是不是错句?不是be busy doing sth?为什么没有sth?be busy doing是谓语动词? be afraid of 后面为什么加to do ,而不是doing?