to stop trying to do something because you have realized that you cannot succeed

認輸;覺得成功無望而放棄

throw in the towel字面意義是“丟毛巾進去”。拳擊比賽時，教練如果判斷他的選手不能獲勝，有時會叫助手扔條毛巾進入場中(throw in the towel)，裁判就會立刻停止比賽。因此，throw in the towel就代表“投降”的意思。

I was ready to throw in the towel, but I stayed with it.

我準備認輸了，但是我還在堅持。