1go off at a tangentBritish EnglishBrE, go off on a tangentAmerican EnglishAmE informalTHINK/HAVE THE OPINION THAT to suddenly start thinking or talking about a subject that is only slightly related, or not related at all, to the original subject 突然离开原来的思路;突然离题
Let’s stay with the topic and not go off at a tangent.
我们还是继续讨论正题吧,不要离题。
Examples from the Corpus
go off at a tangent• As for going off at tangents, my dear, I do it myself, hormonebalance not withstanding.• Loretta's mindwent off at a tangent.
2.technicalHM a straight line that touches the outside of a curve but does not cut across it 切线