问题补充：
The holiday we had been looking forward to at last.
A. arriving
B. would arrive
C. arrived
D. have arrived
答案：
A. arriving
B. would arrive
(答案→)C. arrived
D. have arrived
解析：考查句子结构。本题很容易错选A。实际上we had been looking forward to是一个定语从句修饰the holiday.句子的主干：The holiday arrived at last.
