would attend,这里whether相当于if是是否的意思,应该用将来时语态；如果没有I,应该填to attend.
the next day不同于next day,the next day引导过去时,next day引导将来时,因为前后时态要一致,所以应该填would attend.不对啊，虽然我也是觉得是will attend,但是答案是would attend.因为是the next day,引导过去时，因为前后时态要一致，所以would attend