他会说中文吗?Does he speak Chinese?
他是中国人吗?Is he Chinese?
那为什么一个用does一个用is
老师来教你
一般疑问句有动词原形就用do/does
speak是动词原形,所以用do或does
Does he speak Chinese?他会说中文吗?
Do you speak Chinese?你会说中文吗?
没有动词原形用be动词:am is are
Chinese是名词,所以用be
Is he Chinese?他是中国人吗?
Am i Chinese ?我是中国人吗?
Are you Chinese?你是中国人吗?