Can’t see the wood for the trees 英文諺語
Can’t see the wood for the trees 見木不見林，逐末而忘本
Also: Can’t see the forest for the trees.
If you can’t see the wood for the trees, you can’t see the whole situation clearly because you’re looking too closely at small details, or because you’re too closely involved; if someone can’t see the wood for the trees, they are unable to understand what is important in a situation because they are giving too much attention to details.
“Fred is so focused on product details that he can’t see the wood for the trees when it comes to the overall needs of the company.”