单选题 The nuclear family ______ a self-contained, self-satisfying unit composed of father, mother and children.

【正确答案】 A

【答案解析】refer to提到，说到，涉及到；define解释，阐明，给……下定义(通常用于 define sth．as结构中)；describe描写，形容；devote to把……献给，贡献于。