In English, we say "yes" and "no." In Chinese, you often repeat the verb. To agree, say 是 (shì) - yes (it is). To disagree, say 不是 (bú shì) - no (it is not). For verbs like "to have," you would say 有 (yǒu) for "yes, I have" and 没有 (méiyǒu) for "no, I don't have."