"The men read."
Translation:De mannen lezen.
You're right, it could go both ways. Unfortunately, we can't specify the context, but we can accept a past tense answer in Dutch (i.e. "De mannen lazen.").
All nouns in plural have the definite article "de" (as compared to nouns in singular that can have either "de" or "het) :-)
Why is it necessary to have an determiner before men? a previous sentence just started with meisjes with no De before it.
There's a definite article to show that they are particular men, not just any random group.