单选题 ______ a fine day, we decided to go out for a picnic.
A. Having been B. Being C. What D. It being

【正确答案】 D

【答案解析】[解析] 本题考查学生对独立主格结构的理解。原句应为：Because it was a fine day, we decided to go out for a picnic．由于主句与从句主语不一致，用省略形式时必须把从句的主语加上，从句的谓语动词用非谓语动词形式。所以答案为D。