"She knows a lot about banks."
Translation:Sabe mucho de bancos.
'ella tiene muchos conocimientos sobre los bancos'
According to Spanishdict.com, this is a properly constructed sentence and means 'she knows a lot about banks' Dl says no.
That website translates 'She knows a lot about banks as:
Ella sabe mucho sobre los bancos -or- sabe(conoce) mucho sobre bancos
Does "de" in this sentence imply "about"? Or does it simply say "she knows a lot of banks"? And no "los"? Other times, when it's an indifined and unspecified quantum like now, I've gotten it wrong to not use las/los. So why now? I wrote: Ella sabe mucho acerca de los bancos.
If a noun is a subject and https://www.spanishdict.com/guide/using-the-definite-article-in-spanish . I'm still not 100% sure. One thing that helped a lot was being told you use one when a noun follows gusta or gustan.