set something off
phrasal verb with set verb uk/set/ us/set/ setting | set
(CAUSE)
C2 引起，引发（常指一系列事件）
to cause an activity or event, often a series of events, to begin or happen
The court's initial verdict in the police officers' trial set off serious riots. 法庭审理这起警官案件作出的初审判决引起了严重的暴乱。
C2 使发出巨响；使爆炸，引爆
to cause a loud noise or explosion, such as that made by a bomb or an alarm (= a warning sound) to begin or happen
Terrorists set off a bomb in the city centre. 恐怖分子在市中心引爆了一颗炸弹。
Somebody set the alarm off on my car. 有人触发了我车上的报警器。
(MAKE NOTICEABLE)
（通过对比）使更有吸引力;衬托
to make something look attractive by providing a contrast (= attractive difference) to it
The new yellow cushions nicely set off the pale green of the chair covers. 黄色的新靠垫把浅绿色的椅套衬托得很好看。