(also an alarm bell goes off/rings/sounds)敲响警钟;发出危险预警
used to describe an occasion when you realize that there may be a serious problem or danger
When Frank suggested coming to stay for a couple of days, alarm bells started to ring in my head. 当弗兰克建议来住几天时，我的脑海里响起了危险预警。
Alarm bells went off in the industry when the law was proposed. 当这项法律被提议时，该行业内响起了警钟。
Suddenly, something caused an alarm bell to go off in my head.
When he heard who they had chosen to promote, alarm bells rang.
I'm not sure why, but an alarm bell sounded in me.
See also: alarm bell