"They drank beer at my house."
Translation:Ellos bebieron cerveza en mi casa.
I feel like I'm progressing and then I get 'la cerveza' wrong as well. I think because it is a class i.e beer in general we can omit 'la'. I have been asking about this but no responses. I have researched and while I can get some specific rules they don't give a complete picture. I will keep asking.
It depends on when the event occurred and if it is finished. There are also differences between spain and america. I suggest you take a look at: http://www.esfacil.eu/en/verbs/5-modes-and-tenses-in-spanish.html