Okay, so in a nutshell walk as a verb, so does take an S If it's the third person singular work as a noun is uncountable unless it means pieces of art or pieces of literature and the word homework is also uncountable.
好吧,簡而言之,步行作為動詞,如果是第三人稱單數,那麼就需要一個S,工作作為名詞是不可數的,除非它是指藝術作品或文學作品,而家庭作業這個詞也是不可數的。