"They do not stop drinking."
Translation:Ellos no dejan de beber.
You can find on line lists of Verb infinitives that are shown against their paired prepositions. De, A, or sometimes no prep just straight joining of two verbs. And sadly, yes you just have to memorise each pairing!
"Terminar" is used more along the lines of ending or even finishing something. For example, to say "I'm done," you'd say, "ya terminé."
The translation I decided to use is "Ellos no detienen beber." Is my use of "detener" incorrect here? Duolingo seems to want me to use "dejar de" in these contexts.
Detener would not be used in such a situation. It is more along the lines of stopping something or someone else. So for example: La policia detiene el ladrón. = The police arrests the burglar. Yo detengo la maquina. = I stop the machine. Dejar is used to indicate someone stopping doing something (an action) himself. Yo dejo de beber. = I stop drinking.
They apparently go together like peas and carrots as Forrest Gump would say. The hover definition hint even shows it.
It's one of the "perifrasis verbales". It's just a construction, where the meaning of the main verb in a construction like that gets altered. Dejar de (Inf) = acabar de (inf) = to finish doing something. http://www.materialesdelengua.org/LENGUA/morfologia/perifrasis/perifrasisverbales.htm
Anyone know why we use the infinitive 'beber' at the end VS the conjugated 'beben'? I don't really understand why it needs to be the infinitive.