The students are busy ___(listen) to the teacher.
问题描述:
The students are busy ___(listen) to the teacher.
答
Be busy doing sth是一个固定句型,所以应该是
The students are busy listening to the teacher.
答
listening
be busy doing 固定搭配
答
The students are busy listening to the teacher.
学生们正忙着听老师(讲课)
be busy doing sth,是固定词组,意思是忙于做某事