"You are eating a sandwich."
Translation:Vous mangez un sandwich.
It might be obvious, but I'd like to make it clear that originally genderless foreign nouns are masculine. If the original language has genders, then the same gender will be adopted; hence we say la paella, la mozzarella, la moussaka, la merguez, la perestroika...
(spot the odd one out)
In English, to mean that an action is in progress at the time you speak, you use the continuous verbal form, ie verb BE + action verb in the gerund form (-ing).
o he is eating means he currently eats
In French, this verbal form does not exist (direct translations like “il est mangeant/manger/mange” are incorrect).
Therefore, you can translate the continous present to “il mange” or “il est en train de manger”, where the construction with the verb "être" + en train de + infinitive correctly expresses the English continuous form.