the blind leading the blind从字面上直译就是“盲人教瞎子”，明明两个人都看不见路，其中一位还要给另一位领路。泛指“外行指导外行”。

【例句】
It's hard to believe that they chose him as their new leader. It's like the blind leading the blind.
很难相信他们选择他作为他们的新领导人。这就像瞎子给瞎子引路。

I don’t know why she asked me to show her how the computer works when I’ve hardly used it myself. It would be a case of the blind leading the blind.
我自己都没怎么用过电脑，不知道她为什么要我教她怎么用。这可真是瞎子给瞎子引路。