They are busy _____ .

分类: 笔试(00004) 发布时间: 2024-08-16 05:27 浏览量: 0
They are busy _____ .
A、to do this
B、doing this
C、to this
D、did this
【正确答案】:B
【题目解析】:B busy 后跟动名词,be busy doing sth 忙着做...... 。