"The sick men are in the forum."
Translation:Aegri sunt in foro.
I think this is part of the course being in "Beta": Not all possibilities have been included yet.
I reported two or three English sentences today in which I used perfectly normal word orders. These will be included in the set of correct answers. The same applies to the Latin word orders (but with Latin I'm not as confident in reporting as in English).
I think it is important that we continue reporting the sentences that we definitely know are correct, following this guideline: https://forum.duolingo.com/comment/33853120
In this way, the number of problems will be reduced.
It depends on the sentence. It's ablative if there is no change in state. In other words if you start and end the action in the market, then it's foro. If you start and end in school, it's ludo. If you start outside the market and go INTO it, it's forum, and if you go INTO the school, it's ludum. Generally, if "in" can be translated as "into", then it's accusative (forum/ludum). But if not, it's ablative (foro/ludo)
Nominative vs ablative. We're saying where the men are, so it's "in" plus the ablative case.
Here is a plain-English overview of what the cases are and how they work:
Latin cases, in English
Adjectives must agree in gender, number, and case with the nouns they modify, but they have their own declensions. Sometimes you get lucky and the adjective just happens to follow the same declension as the noun, but that is not a guarantee.
For good measure, here are the verb conjugation charts:
Latin verb forms