I am Chinese.中Chinese前用不用加a?

I am Chinese.中Chinese前用不用加a? I am Chinese.为什么Chines前不用冠词a? I am a Chinese. I am a Chinese girl.为什么不用:I am an Chinese girl. I am not Chinese boy I am not a Chinese 为什么后者要加a那 I am a Chinese对Chinese划线提问用什么 I am a chinese还是I am chinese正确 是i am a chinese 还是 i am chinese I am a Chinese还是I am Chinese I am a Chinese和I am Chinese哪个对? I am Chinese.I am a Chinese.哪个句子正确 i am proud i am a chinese