touch something ↔ off phrasal verbphr v START something/MAKE something STARTto cause a difficult situation or violent events to begin 使产生〔困境〕;引发〔暴力事件〕 It was these national rivalries that eventually touched off the First World War. 正是国家之间的这些敌对行为最终引发了第一次世界大战。
touch off• But this was just a shrewd touch that came off.• An incident with a couple of heavy-handed cops touched it off, and the riot was on.
→ touch something ↔ off at touch1(PHRASAL VERB)