名詞 blind alley:

1. a street with only one way in or out
   同義詞：cul de sac, dead-end street, impasse
2. (figurative) a course of action that is unproductive and offers no hope of improvement

1. We tried one idea after the other, but they all seemed to be leading to blind alleys.
   我們想了一個又一個主意，但它們似乎都行不通。