The positive forms need only a verbe (be careful  with the s for he she it)
the interrogative forms need an auxiliary as well as the negative forms except with to be
EX: I ike him (s+v)
       Do you like hiM?  (aux +sujet+verbe
       I do not like him    (sujet +aux+not+ verbe

I have a pen. Do you have a pen? NO, I don't have a pen

(I am rich Are you rich? Iam not rich)