(偶然)发生:What has happened here? 这里发生了甚麽事?/ Accidents will happen in the best regulated families. [谚] 家规再严,丑事难免。 2. 碰巧:I happened to be there when he needed me. 在他需要我时我碰巧在那儿。/ It just so happened that I had no money with me. 碰巧我没带钱。《习语》 happen on (upon) 偶然碰见某人或某物