The only difficult part was threading the cotton through the eye of the needle!

唯一困难的部分是将棉线穿过针眼！

《柯林斯英汉双解大词典》

The trick is to find the eye of the needle-the spots on the graph where there are breaks in the ranks, leading an investor to the ideal marketplace in which to do battle.

秘密在于找到针眼，即图上排列阵容的空白点，从而引导投资者找到大展拳脚的理想市场空间。

youdao

That's what writing is: a bunch of small things, tiny things, infinitesimal things that you can hardly see-smaller than the eye of a needle.

写作何谓：就是一堆你几乎看不到的小事儿、小事儿、无穷小的事儿，小到比不上一枚绵针的针眼。

youdao

Deserters from the Austro-Hungarian army found this made it the perfect hideout - at the head of one valley the pathway passes through the 'eye' of a needle of rock, and from here foolhardy Imperial Army inspectors could be dispatched with a cosh over the head.

BBC: Snowbound Slovenia

It is easier for a camel to pass through the eye of a needle than for a rich man to enter the Kingdom of Heaven.

BBC: Number free facts

From the valley below, each pier and mast merge to look like a single needle with an elongated eye: Foster's drawings, in fact, depict a thread piercing the eye of a needle.

WSJ: A Concrete Ribbon Through the Clouds | Millau Viaduct | Masterpiece by Joseph Giovannini