答案：A
解析：此句中,we have been looking forward to是days的定语从句,也就是说应该是 we have been looking forward to the days,所以句子的主干应该是剔除掉定语从句部分,只留下：The days ___ soon.这样你看应该选哪个?
句意：我们一直期盼的日子就要来临了.