The wonderful time they had been looking forward at last.
A. to arrive
B. to arrived
C. to arriving
D. should arrive
网友回答
A. to arrive
(答案→)B. to arrived
C. to arriving
D. should arrive
解析：
考查时态。句意：他们一直盼望的美好时刻终于到了。they had been looking forward（盼望）后面缺少介词to，结合语境可知本句描述的是过去发生的动作，故用过去时态。故选B。