Definition
This idiom is used to describe a situation where someone is fortunate enough to avoid an unpleasant or embarrassing situation due to a sudden interruption or ending, usually when they were about to have to do or say something undesirable.
解困，解围
The fire alarm went off just as I was about to explain why my report was late; I was saved by the bell.
就在我要解釋為什麼報告遲交時，火警警報響了；我真是被救了。
The power went out during the heat of the debate; it was a case of being saved by the bell for me.
辯論正激烈時停電了；我真是被救了。
I was about to answer a very difficult question when the phone rang; I was definitely saved by the bell.
我正要回答一個非常困難的問題時，電話響了；我真是被救了。