Burglar alarms at any time of the day or night serve only to annoy.
A. go off
B. that are going of
C. that go off
D. which going off
网友回答
A. go off
B. that are going of
(答案→)C. that go off
D. which going off
解析：通过分析句子结构，其中包含一个定语从句，根据at any time of the day or night可知，应该使用一般现在时，故选C。