Definition
to initiate a sudden onset of challenging or tumultuous events
引起；激发
His comments touched off a heated debate.
他的言论引发了一场激烈的辩论。
The protest was touched off by a few new policies.
抗议活动是由几项新政策引起的。
The plot of the movie touched off my memories of the past.
这部电影的情节触发了我对过去的回忆。