【正确答案】Inflection indicates grammatical relations by adding inflectional affixes．such as number, person, fifliteness, aspect and case; and when inflectional affixes are added, the grammatical class of the stems(to which they are attached)will not change．For instance，car/cars, open/opened, boy/boy's．

【答案解析】[解析] 本题考查形态学领域涉及的重要概念——曲折变化。