这两个品种很难辨别。

It's difficult to differentiate between the two varieties.

《牛津词典》

虽然很难辨别哪些包裹里装的是社会保障支票等重要物品，但美国邮政（USPS）和联合包裹服务公司（UPS）会尽其所能优先处理敏感材料。

It can be hard to identify which parcels are carrying crucial items such as Social Security checks, but USPS and UPS try their best to prioritize sensitive material.

youdao

真相扑朔迷离，很难辨别。

The truth is hard to tell.

youdao