looking for a needle in a haystack點解

這是成語來的
同中文"大海撈針" 一樣意思
只不過haystack係乾草, 一堆堆果隻
Looking for a needle in a haystack 即係話響一堆乾草入面搵支針, 意指果件事好難完成, 幾乎冇可能咁滯

(idiom成語)a thing that is almost impossible to find大海撈針
E.g. Searching for a man in this city is like looking for a needle in a haystack.