釋義：

Stack：干草堆；Something that is extremely difficult to find. Anything that's on the verge of being impossible.很難找到的東西，也就是大海撈針；

來源：

Today, this phrase is typically said as "It's like trying to find a needle in a haystack." 現在，這個詞組更多地說法是It's like trying to find a needle in a haystack. This is considered to be an extremely difficult thing to do, and rightly so.這被認為是很難做到事情。 Finding a tiny needle in a big stack of hay, while not impossible, would take a considerable amount of time and effort.也不是說不可能，但干草堆里找針需要花費很大的精力和時間。 Hence, when people are having trouble finding things in modern times, they often say this phrase to indicate the difficulties they are having.因此，當人們很難找到某種東西的時候，他們通常會用到這個詞組去描述。

As for where the phrase originates from, I don't think it's entirely clear. 關于這個詞組的來源具體不是很清楚。My guess would be farmers because I imagine them working with stacks of hay the most out of anyone. 不過合理的猜想應該是這個詞組與農民有關，因為他們經常在和干草堆打交道。Here's what is known: 根據記載，This phrase is written in a old book titled The Complete Works of Washington Irving, published in 1834. 這個詞組被用在一本名叫The Complete Works of Washington Irving 出版于1834年的古書里面。其中寫道：

"If I want to find any particular article, it is, in the language of an humble but expressive saying, -- 'looking for a needle in a haystack.'"意思就是：如果我想找一個謙遜但又有表現力的句子的話，那就可以用大海撈針來形容。

舉例：

1. Searching for my keys in the garden is like trying to find a needle in a haystack.

在院子里找我的鑰匙就好像是在大海里撈針一樣困難。

2. He tried to find his lost contact lens on the beach, but it was like looking for a needle in a haystack.

他在海灘下找遺失的隱形眼鏡，但這好比是大海撈針，希望渺茫。