I have to explain to my students why we say "She has a brown jacket." (We use the verb to have in third person present tense.) But we say "Does she have a brown jacket?" (We use the infinitive to have because it's a question.) What is the name for the grammatical construction "Do you +infinitive?" and "Does he +infinitive?" What do we call it?
It happens with future questions too: "Are you going to +infinitive?", and "Will they +infinitive?". What is that structure called? How can I best explain it to them? They are Spanish speakers.