英语翻译（2）我记得以前说：I'm a Chinese ,但好像也说过:I'm Chnese 难道后者意为 我是中国人,

1) 不妥.
我假定楼主想表达的意思是：他能说流利的英语.
He speaks English fluently.
He speaks fluent English.
He is 之后的动词应是-ing,应是是speaking.
但是类似"他说流利的英语”这种表达,用简单现在式即可.
He speaks good French.
She cooks well.
I speak fluent German.
2) I am Chinese,或是 I am a Chinese man/girl.
不过,楼主要表达国籍的话,说I am Chinese即可.
如：I am Peruvian.I am a Peruvian citizen.
I am American.I am an American native.
I am Malaysian.I am a Malaysian soldier.
有"a"的话,Chinese就变成了形容词,因此后面得加名词.
如a Chinese man,a Chinese girl,a Chinese student,等等.
希望能帮到楼主!:)