1、They are busy (write) homework.空格里填的是writing,

问题描述:

1、They are busy (write) homework.空格里填的是writing,
为什么?有什么可以让write加ing的理由吗?
A、with;fix
B、with;dancing
C、on;dance
D、on;fining(答案是B,为什么?)
I'm busy for the party.

1writing (be busy doing sth) 固定句型必须背哦
2 B (be busy with doing sth 忙于做某事)也要背哦