1
a needle in a haystack
固定习语，意为“极难找到的东西”，常与 look for / search for 连用。
Finding a good book in this library is like looking for a needle in a haystack.
在这个图书馆里找到一本好书就像大海捞针。
干草堆
先理解核心含义，再看它在真实句子里的用法。
干草堆
a stack of hay
Finding a good book in this library is like looking for a needle in a haystack.
在这个图书馆里找到一本好书就像大海捞针。
干草堆。
A mound, pile, or stack of stored hay.
急流中的驻波。
A standing wave in a rapid.
在其中搜索另一字符串的文本字符串。(参见:大海捞针)
The text string within which another string is searched for. (see: needle in a haystack)
泛指搜寻难以找到的稀有事物的场所或物品集合。
Any place or collection of items through which one searches for something that is rare and hard to find.
The farmer built a tall haystack in the corner of the field.
农夫在田地的角落里堆了一个高高的干草堆。
The children hid behind the haystack during their game of hide-and-seek.
孩子们玩捉迷藏时躲在干草堆后面。
In autumn, farmers often make haystacks to store feed for the winter.
秋天，农民们常常堆起干草垛，为冬天储存饲料。
固定习语，意为“极难找到的东西”，常与 look for / search for 连用。
Finding a good book in this library is like looking for a needle in a haystack.
在这个图书馆里找到一本好书就像大海捞针。
haystack 是可数名词，复数形式为 haystacks。这里展示用不定冠词 a 修饰单数名词的结构。
In the meadow stood a tall haystack.
草地上立着一个高高的干草堆。
from ... to ... 结构表示从一个到另一个，这里强调连续经过多个干草堆。
The children ran from haystack to haystack, playing hide-and-seek.
孩子们从一个干草堆跑到另一个干草堆，玩捉迷藏。
Not this
I saw many haystack in the field.
Use this
I saw many haystacks in the field.
haystack 是可数名词，复数形式为 haystacks；many 后接可数名词复数，不能用单数。
Not this
He is looking for a needle in haystack.
Use this
He is looking for a needle in a haystack.
haystack 是单数可数名词，前面需要冠词或其他限定词；表示泛指的“一个干草堆”时用不定冠词 a。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
大海捞针；极难找到的东西
Finding a parking spot in the city is like looking for a needle in a haystack.
在城里找个停车位就像大海捞针。
大海捞针；极难找到的东西
Finding a parking spot downtown on a Saturday is like finding a needle in a haystack.
周六在市中心找一个停车位就像大海捞针一样。
Use haystack naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
把 hay（干草）堆成 stack（堆），就是 haystack；还记得“大海捞针”要找的那个干草堆吗？
语域：neutral 常见场景：农田、文学作品、日常交谈 该词通常指干草堆，多用于描述农村场景或文学比喻，语气中性，正式与非正式场合都比较常见。
Genuine matches: 'hay' shares the initial /heɪ/ segment; 'stack' shares the final unstressed /stæk/. Note that back, hack, and tack end in the same -ack spelling and /æk/ sound, but none rhymes with haystack because its main stress is on the first syllable. Haywire begins with the same 'hay' but then differs completely (/ˈheɪwaɪər/ vs /ˈheɪstæk/).
Dictionary facts from ECDICT, WIKTIONARY.