是busy doing sth.还是busy to do sth.
问题描述：
是busy doing sth.还是busy to do sth.
答
be busy (in) doing sth
be busy with sth
没be busy to do
答
busy doing sth
答
busy doing sth.忙于做某事.
busy to do sth.这是错误的结构,不存在!