We have a lot of homework. We are very busy today. A. to doB. doingC. to doingD. do

问题补充：

We have a lot of homework. We are very busy today.

A. to do

B. doing

C. to doing

D. do

答案：

(答案→)A. to do

B. doing

C. to doing

D. do

解析：句意：我们有很多作业要做。我们非常忙。have sth to do.有某是要做。故此处用动词不定式to do.故选A。