Let's (go) ... to the zoo

ex1
let's(go) to the zoo
how about (go) on foot?
he(want) (be) a docter
why.....we ( not GO) to the cinema?
ex2 there is one mistake
we no wear a uniform at out school
how many childs does your sister have?
i am going to the post ofice for buy some stamps
tim and tom bothh ảe having blond hair and blue eyes
linh is chinese she has drank brow rhairs