I am a Chinese.还是不能要那个"a"?

I am a Chinese.还是不能要那个a? I am a Chinese还是I am Chinese 是i am a chinese 还是 i am chinese I am a China girl还是Chinese - What is your nationality?- I am a Chinese 还是 I am Chinese 还是都行 I am from China.的同义句是I am a Chinese.还是I am Chinese.还是都行 i am proud i am a chinese I am not Chinese boy I am not a Chinese 为什么后者要加a那 为什么不能说I am an English?我们可以说I am a Chinese.和I am English. 要表达我是中国人应该说I am Chinese为什么不说I am a Chinese? I am Chinese.I am a Chinese.哪个句子正确 英语翻译翻译：我是中国人我只想知道是“I am a Chinese”还是“I am a chinese people”， I am a chinese boy.这个 chinese boy前面要加a吗? I am Chinese.VS I am an American.有人说：只有I am Chinese.没有（或者说不正规）I am a Chinese.那为什么有I am an American.(我认为有)顺便问下在“I am Chinese”中,Chinese是名词还是形容词? I am a Chinese对Chinese划线提问用什么 I am Chinese.中Chinese前用不用加a? I am a chinese还是I am chinese正确这个语法我搞不清楚,我是一个中国人,不知道该这样表达, help:should i say :i am a chinese or i am chinese