You cook - She ...А тут She cooks, потому-что тоже does? They fly - It ... I clean - She ... I buy - He ... You like - He ... I do - She ... We walk - He .. шестой класс

She cooks, потому что в конце глаголов после he, she, it пишется "s".
You cook - She cooks; They fly - It flies; I clean - She cleans; I buy - He buys; You like - He likes; I do - She does; We walk - He walks.