没有抓住机会会怎样？就会“痛失良机”了，“让什么东西从你的手指尖溜走”就表示“痛失机会”，例如：You can’t be more stupid! How could you let such a golden opportunity to make big money slip through your fingers? It was an opportunity that comes once in a blue moon. （你真蠢！这样一个发大财的机会千载难逢，你怎能眼睁睁的让他跑掉那？）这里的 once in a blue moon 就是指“千载难逢”。