【正确答案】Concord, also known as agreement, is the requirement that the forms of two or more words in a syntactic relationship should agree with each other in terms of some categories．

【答案解析】[解析] 本题考查一致关系的概念。一致关系，又称为协同关系，指两个或更多处于一定语法关系中的词，要在某些范畴上互相保持一致的形式。