be busy doing等于什么

be busy doing等于什么 be busy doing sth等于什么这句话The CEO is busy signing files.等于什么 busy的用法be busy with后面加什么词be busy in doing与be busy with doing与be busy doing有什么区别 be busy in 的用法?它和be busy doing, be busy with有什么区别? be busy doing造句 be+busy+doing=be+( )+( be busy加什么?be busy是接doing sth还是to do sth? be busy doing 和 be busy in doing 的区别? be busy with doing 与be busy doing 区别 be busy doing sth 例句 be busy in doing sth be busy doing 过去式+造句 be busy doing 是不是省略了in 应该是 be busy in doing 还有 上面两个跟be busy with 有什么区别么 be busy doing中doing什么成分那个句子能说明呢？给个例句 be busy with sth 与be busy doing sth be busy doing还是be busy to dokuai 为什么是be busy doing而不是be busy to do be busy to do 还是 be busy doing