He is English.不加an

He is an English 为什么she is English girl.不加an. he is an english teacher. 合并句子he is an English boy.Jim is an English boy,too.he is an Is he an English boy.复数形式 为什么不能说He is an English He is English.He is an English.He is an English man.三句是否可互划等 Jim is ( ) English.He is ( ) English boy.A.an;an B./;an C./; He is an Englishman.为什么不是He is an English.可不可以He is a Chines I guess______name is peter,he is an English boy . She is an English girl.He is E(),too. Jack is English.He is an English boy.为什么第一个English不用冠词?