当主语为非第三人称单数,如：I / you / they/ we 等时用have
如：We have a big classroom.
I have waited for you for about two hours.
但主语为第三人称单数,如：he/ she/ it 等时用has
如：My sister has a nice watch.
Tom has already finished doing his homework.
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不明白的再问哟,请及时采纳,多谢!