这句话：He knows six languages,that is Chinese,English,French,Spanish,Russian,and Portuguese.
that is用变成those are吗? that is前用加逗号吗?

用法错误,that is 只用在单数上,有六种语言,则不能用,而且句子的语法表达上亦有错,应该是:
He knows six languages,which are Chinese,English,French,Spanish,Russian,and Portuguese. 才对.

That is 的用法如下:

He can speak one foreign language, and that is English.
He has something, which I don't have and that is call talent.
That is one of the world's most advanced technologies.
What a beautiful house that is!
等等.

很希望我的回答会对你有帮助.如有不明白,可以再追问,若满意请采纳,谢谢你,并祝你进步! 这句话：He knows six languages,that is Chinese,English,French,Spanish,Russian,and Portuguese.
that is用变成those are吗? that is前用加逗号吗?

用法错误,that is 只用在单数上,有六种语言,则不能用,而且句子的语法表达上亦有错,应该是:
He knows six languages,which are Chinese,English,French,Spanish,Russian,and Portuguese. 才对.

That is 的用法如下:

He can speak one foreign language, and that is English.
He has something, which I don't have and that is call talent.
That is one of the world's most advanced technologies.
What a beautiful house that is!
等等.

很希望我的回答会对你有帮助.如有不明白,可以再追问,若满意请采纳,谢谢你,并祝你进步!