I am an American还是I am an American man那句话对?因为American有美国人的含义,是否可以不加man?

I am an America(n) boy.用America还是American? I am an American.改为复数句子. I am an American还是I am an American man那句话对?因为American有美国人的含义,是否可以不加man? I come from ____ .I am an ____.应该选England；English还是America；American 把I am an american boy改为一般疑问句 i am an __boy?a:england b:american急,1 I'm American,I'm an American和 I'm an American girl这三种表达方式都可以吗?如果可以的话,I'm an American里American 是名词,那I'm American里的American是名词还是形容词? 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? 在英语中可数名词能不能单用例如,我是美国人（I am an American.)能不能说成是（I am American.) 用什么提问 回答I am an American用What is your nationality?提问,回答I am Amarican;那用什么提问回答I am an American She is an American .这里加不加冠词?American 大写否?I am (a) Chinese 加不加a I come from America.i come from America.I am from America,I am an American.有什么区别? 为是么不能说I am an English?那I am a chanese I am a Japanese又对吗?若是I am an American呢? Hello,I am an American,I want to ask a question,what is 给力? I'm Nancy.I'm an American I'm an American,I‘m American,I'm an American girl.都可以吗 He is American.I am English.为什么不能加冠词He is American.I am English.和He is an American.I am a Englishman.的中文是不是没有区别呢 Which is the best website for Chinese learning? I am an American in Ohio in US.