He plays the piano. Does he play the flute?
Japanese name: 3人称単数現在形 (san-nin-shou tansuu genzai-kei)
She plays tennis every Sunday.
Makoto doesn’t like onions.
Does your grandmother live in London?
In English, the form of the verb changes when the subject is in the third person. It becomes “pluralized,” for lack of a better term. As with many verb form changes, there are general rules for spelling, but plenty of exceptions as well.
In the negative and question sentences, the word “does” or “doesn’t” is pluralized and the verb remains in its plain form.
English is very unique among the world’s languages in that this only applies when the subject is in the third person. Even very advanced students will occasionally make mistakes with this grammar point.